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Anion Pairs Template a Trigonal Prism with Disilver Vertices
- John P. CarpenterJohn P. CarpenterDepartment of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.More by John P. Carpenter
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- Charlie T. McTernanCharlie T. McTernanDepartment of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.More by Charlie T. McTernan
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- Tanya K. RonsonTanya K. RonsonDepartment of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.More by Tanya K. Ronson
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- Jonathan R. Nitschke*Jonathan R. Nitschke*[email protected]Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.More by Jonathan R. Nitschke
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Abstract
Here we describe the formation of a trigonal prismatic cage, utilizing 2-formyl-1,8-naphthyridine subcomponents to bind pairs of silver(I) ions in close proximity. This cage is the first example of a new class of subcomponent self-assembled polyhedral structures having bimetallic vertices, as opposed to the single metal centers that typically serve as structural elements within such cages. Our new cage self-assembles around a pair of anionic templates, which are shown by crystallographic and solution-phase data to bind within the central cavity of the structure. Many different anions serve as competent templates and guests. Elongated dianions, such as the strong oxidizing agent peroxysulfate, also serve to template and bind within the cavity of the prism. The principle of using subcomponents that have more than one spatially close, but nonchelating, binding site may thus allow access to other higher-order structures with multimetallic vertices.
Self-assembly allows the efficient construction of complex architectures from relatively simple components. Polyhedral metal–organic cages are a class of such architectures that have been the focus of intense recent work. (1−3)
Much effort has gone into the design of multitopic organic ligands for these cages. The symmetries and connection properties of these ligands and their metal-ion partners (typically octahedral (4,5) or square planar (6,7) transition metals) can be used to create structures with diverse functions. (8,9)
A key feature of these cages is the presence of an internal cavity of well-defined shape, size, and charge density. These cavities may offer chemical environments distinct from that of the bulk solvent. They have thus found applications in areas such as molecular sequestration, (10−12) chiral sensing, (13) and the stabilization of reactive species (14) and reaction intermediates. (15,16)
Novel architectures and functions can be obtained through the use of flexible organic building blocks. (17,18) Many systems that incorporate such species form unexpected and often structurally complex architectures, including a range of intricate cages and grids, (19−21) which have been used for catalysis, (22) guest binding, (23) and molecular knot formation. (24,25)
We hypothesized that novel coordination motifs could be used in an analogous way to these flexible ligands. Complexes that contain two metal ions in close proximity are an area of active interest, particularly in catalysis. (26,27) Such bimetallic complexes can adopt a variety of configurations, displaying features such as anion inclusion, (28) the incorporation of different numbers of ligands, (29) or metal–metal bonding. (30)
We reasoned that the nonconverging coordination vectors of commercially available 2-formyl-1,8-naphthyridine, (31,32) along with the flexible coordination sphere of silver(I), (33−35) could lead to the formation of architectures with unprecedented geometries. Here, we report the preparation of a AgI12L6 trigonal prism using the subcomponent self-assembly approach. (36,37) This structure makes use of bimetallic units to define the vertices of a three-dimensional metal–organic structure, opening the door to further investigation of new polyhedral architectures in this class of compounds. It is also the first example of this type of prismatoid constructed with 3-fold symmetric building blocks, to the best of our knowledge.
The reaction of tris(4-aminophenyl)amine A (6 equiv) and 2-formyl-1,8-naphthyridine B (12 equiv) with silver(I) perchlorate (ClO4–, 12 equiv) yielded AgI12L6 cage 1 (Figure 1), whose composition was confirmed by both ESI- and HR-MS (Figures S8 and S9). 1H NMR spectroscopy revealed 28 signals, consistent with a distinct environment for each ligand arm, with two of the phenyl rings undergoing rapid rotation on the NMR time scale (Figure 2c).
Figure 1
Figure 1. (a) Synthesis of AgI12L6 trigonal prism 1 from tris(4-aminophenyl)amine A, 2-formyl-1,8-naphthyridine B, and silver(I) perchlorate. (b) Assembly of 1 requires an appropriate template anion. (c) X-ray crystal structure of (ClO4–)2⊂1 with the two templating anions included. One pair of ligands is shown in gray to highlight the desymmetrization of the ligand arms. (d) Top-down view depicting the central tubular void of (ClO4–)2⊂1. Disorder, nonincluded anions, and solvent molecules have been omitted for clarity.
Figure 2
Figure 2. (a) One vertex of (ClO4–)2⊂1. (b) Simplified representation of the same vertex. (c) 1H NMR and DOSY NMR spectra (400 MHz, 298 K, CD3CN) of (ClO4–)2⊂1 showing 3-fold desymmetrization of the cage ligands. The units of D are 10–6 cm2 s–1.
Further analysis by diffusion ordered spectroscopy (DOSY) supported the formation of a single product structure in solution, with an observed diffusion coefficient of 4.8 × 10–6 cm2 s–1, corresponding to a hydrodynamic radius of 12 Å (Figure 2c).
Vapor diffusion of diisopropyl ether (iPr2O) into an acetonitrile solution of 1 provided crystals suitable for analysis by X-ray diffraction. The cationic portion of 1 was revealed to have a twisted trigonal prismatic structure (Figure 1c,d) with a pair of silver centers at each vertex.
The vertices of the structure were observed to adopt a new mode of coordination. The two AgI cations at each vertex are coordinated by three distinct naphthyridine-imine arms from different ligands. Two of the arms bridge between AgI centers, using all three N-donors. The third naphthyridine-imine arm only coordinates to the outermost AgI center via two of its N-donors (Figure 2a). The bidentate bridging mode of the napthyridines forces the AgI centers into close proximity, with Ag···Ag distances of 2.816(2)–2.861(3) Å, within the range reported for other naphthyridine-bridged silver complexes. (30,31) All AgI centers are coordinated by four nitrogen donors, with Ag–N bond lengths ranging from 2.227(5)–2.520(7) Å.
The two triangular faces of the trigonal prism, as defined by the locations of the centroids of the disilver centers of each vertex, are twisted by 30 ± 1° with respect to each other. Two tritopic ligands define each rectangular face of the prism, each bridging between three vertices (Figure 1). Two naphthyridine-imine arms of each ligand connect vertices belonging to the same triangular face, while the third arm bridges to a vertex of the opposing triangular face, through the interior of the structure. The connectivity of the structure is thus similar to a D4-symmetric CdII8L8 tetragonal prism with a larger internal cavity and single-metal vertices. (38) In the present case, the overall architecture has D3 symmetry, as well as a much smaller internal cavity.
The three arms of each tritopic ligand thus experience different environments within the overall structure. Further analysis by COSY and NOESY NMR, both 1D and 2D, allowed us to unambiguously assign each of the proton environments in solution. All solution-state structural characterization data for 1 were consistent with the crystal structure (see SI Section 3).
The crystal structure revealed that the triangular prism bound a pair of ClO4– anions within its elongated cavity. Both encapsulated anions benefit from nonclassical hydrogen bonding interactions with internally directed protons of the cage, with CH···anion distances in the range 2.4–2.7 Å. Several other ClO4– anions were found to associate with the periphery of the cage. From this, we inferred that anions may play a crucial role in templating the formation of this architecture.
A series of experiments was carried out to further probe the scope of anion templation. Silver bis(trifluoromethanesulfonyl)imide (AgNTf2) was used as the silver(I) source in all cases. Following treatment of this salt with subcomponents A and B, it was found that no well-defined structure formed in the absence of a competent template ion (Figure S58), even after heating the mixture to 60 °C in an inert atmosphere for 3 days. Molecular modeling, starting from the crystal structure of (ClO4–)2⊂1, suggested that the cavity is too small to accommodate NTf2– anions.
Templation of (X–)2⊂1 occurred following the addition of two equivalents of trifluoromethanesulfonate (OTf –), tetrafluoroborate (BF4–), perrhenate (ReO4–), hexafluorophosphate (PF6–), ClO4–, sulfate (SO42–), or bisulfate (HSO4–) to the untemplated mixture of A, B, and AgNTf2 (SI Section 4). Cage (X–)2⊂1 also formed directly when AgPF6, AgClO4, or AgBF4 was used as the silver(I) source. AgReO4 and Ag2SO4 were not sufficiently soluble in acetonitrile to allow for the reaction to proceed.
The diffusion of diethyl ether into a solution of (OTf–)2⊂1 containing excess TBAPF6 furnished crystals of sufficient quality for analysis by X-ray diffraction, confirming formation of a AgI12L6 cage isostructural to (ClO4–)2⊂1. A clearly resolved hexafluorophosphate (PF6–) anion was observed in one internal site, while the second site contained a disordered mixture of OTf – and PF6– (65%/35% occupancy, respectively, see SI Section 8).
Crystals of (HSO4–)2⊂1 formed following the diffusion of iPr2O into a concentrated MeCN solution, and the structure was analyzed by single-crystal X-ray diffraction (Figure 3a). The distance between the two encapsulated anions was found to be 4.150(2) Å, as measured between the two sulfur atoms. This value is similar to the 4.112(1) Å distance observed by Flood and co-workers, where a pair of HSO4– anions is stabilized by two cyanostar macrocycles. (39,40) In the case of (ClO4–)2⊂1, the Cl···Cl distance was found to be 4.88(2) Å (Figure 3b). These results suggest that hydrogen bonding between the two HSO4– anions within the cage cavity, (41) coupled with interactions between the internally directed protons of the cage and the HSO4–, facilitates close proximity between bisulfate anions.
Figure 3
Figure 3. X-ray crystal structures of (a) (HSO4–)2⊂1, (b) (ClO4–)2⊂1, (c) (PF6–)2⊂1, (d) (EDS2–)⊂1 and (e) (S2O82–)⊂1 with side-views of the isolated anionic templates.
Noting that each crystal structure obtained contained two bound anions, we next explored whether two anions were required to template the framework of 1 in solution. Titration of two equivalents of TBAHSO4 into an untemplated mixture of A, B, and AgNTf2 revealed complete formation of (HSO4–)2⊂1. Addition of further HSO4– led to no appreciable changes (Figure S58). This result, coupled with the crystallographic evidence, suggested that 1 hosts two anions within its central void in solution.
Having observed these supramolecular interactions holding anions in close proximity within 1, we questioned whether linear, covalently linked dianions could also serve as guests and templates for this host. There are few reported examples of such dianions bound inside cage structures. (42,43) Addition of sodium 1,2-ethanedisulfonate (EDS2–) was found to lead to formation of the templated cage. Crystallization by diffusion of iPr2O into an MeCN solution of (EDS2–)⊂1, followed by X-ray analysis, unambiguously confirmed the formation of a 1:1 host guest complex (Figure 3d), as opposed to the 2:1 complexes described above.
We also found that the addition of potassium persulfate (S2O82–), which is known to oxidize AgI to AgII in MeCN solution, (44) led to the formation of cage (S2O82–)⊂1. Diffusion of iPr2O into a solution of (S2O82–)⊂1 in MeCN produced X-ray quality crystals, which revealed a single S2O82– anion bound in the center of the cage’s cavity (Figure 3e). A sulfur–sulfur distance of 4.070(3) Å was measured, shorter than that of the hydrogen-bonded HSO4– dimer. Over the course of 27 days, changes in the 1H NMR spectrum of (S2O82–)⊂1 were observed, consistent with the formation of a new host–guest complex. We thus inferred that the S2O82– was ultimately reduced to other anionic species, which also templated the prism. The 1H NMR spectra of the resulting host–guest species did not match those templated solely by SO42– or HSO4– (see SI Section 6).
The shape and size of cage 1 was observed to adapt to accommodate the different guest anions, as evidenced in the crystallographic data. The volumes of these anions vary from 53 Å3 (for BF4–) to 85 Å3 (for OTf–). (4) Measuring between the centroids of the disilver vertices, significant variations in the conformation of the cage were noted, depending on the guest. While the length of the cage did not vary (<1% change), the apertures at the ends of the cage were found to contract by up to 12 ± 2% (66.9 ± 0.3 Å2 for (EDS2–)⊂1 to 76.3 ± 0.5 Å2 for (OTf–/PF6–)2⊂1, see SI Section 9 for details).
The twist angle between the two triangular faces of the prism was also found to vary. With a twist angle of 0° defining a trigonal prism and 60° defining a trigonal antiprism, 1 varied between 27.5 ± 1.0° (for (S2O82–)⊂1) and 31 ± 0.9° (for (OTf–/PF6–)2⊂1). These twist angles indicate that the geometry of 1 is approximately halfway between an idealized trigonal prism and antiprism.
These changes in the structure of 1 are attributed to two factors: structural tuning of 1 to maximize favorable interactions with the internalized anions and crystal packing effects. Smaller anions led to a contraction of the apertures of the cage, whereas larger anions required the cage to expand to accommodate them. A greater contraction of the triangular apertures corresponds to a greater distortion of the twist angle from that of an ideal prism.
We have thus demonstrated the formation of a desymmetrized trigonal prismatic cage from bimetallic motifs using subcomponent self-assembly. The use of 2-formyl-1,8-naphthyridine allowed the formation of the disilver corners of cage 1, permitting access to this new structure type. The self-assembly process was template-driven, with either two monoanions or an elongated dianion, occupying the central, tubular cavity defined by the cage. The cage flexed and adapted in order to accommodate a broad range of anionic species, including strong oxidants. Further work will look to explore this system in aqueous media and examine the potential uses of its unusual binding pocket. New structures and structure types may also become accessible through the use of other subcomponents that contain spatially close, but nonchelating, binding sites for bimetallic motifs at the vertices of polyhedra.
Supporting Information
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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/jacs.9b05432.
Detailed descriptions of synthetic procedures; characterization of new compounds; spectroscopic data (PDF)
X-ray data for (OTf–/PF6–)2⊂1 (CCDC 1913634) (CIF), (ClO4–)2⊂1 (CCDC 1913631) (CIF), (HSO4–)2⊂1 (CCDC 1913633) (CIF), (EDS2–)⊂1 (CCDC 1913632) (CIF), and (S2O82–)⊂1 (CCDC 1913635) (CIF)
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Author Information
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- Jonathan R. Nitschke - Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.;
http://orcid.org/0000-0002-4060-5122;
- John P. Carpenter - Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.;http://orcid.org/0000-0002-4341-2887
- Charlie T. McTernan - Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.;http://orcid.org/0000-0003-1359-0663
- Tanya K. Ronson - Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.;http://orcid.org/0000-0002-6917-3685
Acknowledgments
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This work was supported by the European Research Council (695009) and the UK Engineering and Physical Sciences Research Council (EPSRC, EP/P027067/1). We thank the EPSRC National Mass Spectrometry Centre (Swansea, UK) for high resolution mass spectrometry and Diamond Light Source (UK) for synchrotron beamtime on I19 (MT15768). J.P.C. thanks the European Union’s Horizon 2020 research and innovation program, Marie Sklodowska-Curie Grant (642192). C.T.M. thanks the Leverhulme and Isaac Newton Trusts, and Sidney Sussex College, Cambridge for Fellowship support.
References
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This article references 44 other publications.
- 1Chand, D. K.; Biradha, K.; Fujita, M.; Sakamoto, S.; Yamaguchi, K. A Molecular Sphere of Octahedral Symmetry. Chem. Commun. 2002, 2486– 2487, DOI: 10.1039/B206625B[Crossref], [CAS], Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotVymu7s%253D&md5=678dce946bca79cbc3180efd41a8e1aaA molecular sphere of octahedral symmetryChand, Dillip Kumar; Biradha, Kumar; Fujita, Makoto; Sakamoto, Shigeru; Yamaguchi, KentaroChemical Communications (Cambridge, United Kingdom) (2002), (21), 2486-2487CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Complexation of tridentate ligand 1,3,5-tris(4-pyridylmethyl)benzene (L) with Pd(NO3)2 leads to the quant. self-assembly of M6L8 mol. sphere (1). 1 Is tetragonal, space group P41/nmm, Z = 4, R1 = 0.1203, wR2 = 0.2800. The av. distance between axially located Pd centers in the giant, hollow sphere of 1 is 15.2 Å.
- 2Freye, S.; Michel, R.; Stalke, D.; Pawliczek, M.; Frauendorf, H.; Clever, G. H. Template Control over Dimerization and Guest Selectivity of Interpenetrated Coordination Cages. J. Am. Chem. Soc. 2013, 135, 8476– 8479, DOI: 10.1021/ja403184a[ACS Full Text
], [CAS], Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXotV2rt7s%253D&md5=7194ccd01d5ec010a14968aa2ff18dd7Template Control over Dimerization and Guest Selectivity of Interpenetrated Coordination CagesFreye, Sabrina; Michel, Reent; Stalke, Dietmar; Pawliczek, Martin; Frauendorf, Holm; Clever, Guido H.Journal of the American Chemical Society (2013), 135 (23), 8476-8479CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors have previously shown that the self-assembly of dibenzosuberone-based bis-monodentate pyridyl ligands L1 with PdII cations leads to the quant. formation of interpenetrated coordination cages [[email protected]]. The BF4- anion inside the central cavity serves as a template, causing the outer two pockets to show a tremendous affinity for allosteric binding of two small chloride anions. Derivatization of the ligand backbone with a bulky aryl substituent allows the authors to control the dimerization and hence the guest-binding ability of the cage by the choice of the templating anion. Steric constraints imposed by L2 (L2 is L1 deriv. by adding substituted phenyl) prevent the large BF4- anion from serving as a template for the formation of interpenetrated double cages. Instead, a single isomer of the monomeric cage [Pd2L24] is formed. Addn. of the small anionic template Cl- permits dimerization, yielding the interpenetrated double cage [[email protected]], whose enlarged outer pockets show a preference for the binding of large anions such as ReO4-. - 3Yazaki, K.; Sei, Y.; Akita, M.; Yoshizawa, M. A Polyaromatic Molecular Tube That Binds Long Hydrocarbons with High Selectivity. Nat. Commun. 2014, 5, 5179, DOI: 10.1038/ncomms6179[Crossref], [PubMed], [CAS], Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVeks70%253D&md5=d6fc892bd2d729096dda6e504ececfadA polyaromatic molecular tube that binds long hydrocarbons with high selectivityYazaki, Kohei; Sei, Yoshihisa; Akita, Munetaka; Yoshizawa, MichitoNature Communications (2014), 5 (), 5179CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)Long hydrocarbon chains are essential components of biomols. used for structure and function in living organisms. The selective recognition and effective binding of hydrocarbons within synthetic host compds. are problematic owing to their conformational flexibility and the lack of specific binding sites. Here we report a mol. tube with polyarom. frameworks prepd. by the Zincke cross-coupling reaction. The tube has a well-defined cylindrical cavity with a diam. and length of ∼1 nm encircled by multiple anthracene panels and thereby binds long hydrocarbons contg. branched Me groups and/or unsatd. carbon-carbon double bonds (for example, heptamethylnonane, nervonic acid ester and squalene) with high selectivity in aq. solns.
- 4Argent, S. P.; Adams, H.; Riis-Johannessen, T.; Jeffery, J. C.; Harding, L. P.; Ward, M. D. High-Nuclearity Homoleptic and Heteroleptic Coordination Cages Based on Tetra-Capped Truncated Tetrahedral and Cuboctahedral Metal Frameworks. J. Am. Chem. Soc. 2006, 128, 72– 73, DOI: 10.1021/ja056993o[ACS Full Text], [CAS], Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1ynsr7J&md5=18aa2207c21aa69f2ae9357882a6a73eHigh-nuclearity Homoleptic and Heteroleptic Coordination Cages Based on Tetra-Capped Truncated Tetrahedral and Cuboctahedral Metal FrameworksArgent, Stephen P.; Adams, Harry; Riis-Johannessen, Thomas; Jeffery, John C.; Harding, Lindsay P.; Ward, Michael D.Journal of the American Chemical Society (2006), 128 (1), 72-73CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two new types of coordination cage were prepd. and structurally characterized: [M16(μ-L1)24]X32 (M = Zn, Cd; X = BF4, ClO4; L1 = 1,4-bis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) are based on a tetra-capped truncated tetrahedral core and have a bridging ligand L1 along each of the 24 edges; [M12(μ-L1)12(μ3-L2)4]X24 (M = Cu, Co, Cd; L2 = 1,3,5-trimethyl-2,4,6-tris(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) are based on a cuboctahedral core which is supported by a combination of face-capping ligands L2 and edge-bridging ligands L1. The crystal structures of 2 of these complexes were detd. The difference between the two illustrates how combinations of ligands with different coordination modes can generate coordination cages which are not available using one ligand type on its own.
- 5Riddell, I. A.; Hristova, Y. R.; Clegg, J. K.; Wood, C. S.; Breiner, B.; Nitschke, J. R. Five Discrete Multinuclear Metal-Organic Assemblies from One Ligand: Deciphering the Effects of Different Templates. J. Am. Chem. Soc. 2013, 135, 2723– 2733, DOI: 10.1021/ja311285b[ACS Full Text], [CAS], Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlemuro%253D&md5=3af02bf70846b96be800f60b8e9db4dbFive Discrete Multinuclear Metal-Organic Assemblies from One Ligand: Deciphering the Effects of Different TemplatesRiddell, Imogen A.; Hristova, Yana R.; Clegg, Jack K.; Wood, Christopher S.; Breiner, Boris; Nitschke, Jonathan R.Journal of the American Chemical Society (2013), 135 (7), 2723-2733CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A rigid org. ligand, formed through the subcomponent self-assembly of p-toluidine and 6,6'-diformyl-3,3'-bipyridine, was employed in a systematic investigation into the synergistic and competing effects of metal and anion templation. A range of discrete and polymeric metal-org. complexes were formed, many of which represent structure types that have not previously been obsd. and whose formation would not be predicted on taking into account solely geometric considerations. These complex structures, capable of binding multiple guests within individual binding pockets, were characterized by NMR, ESI-MS, and single-crystal x-ray diffraction. The factors that stabilize individual complexes and give one over another are discussed.
- 6Jansze, S. M.; Wise, M. D.; Vologzhanina, A. V.; Scopelliti, R.; Severin, K. PdII2L4-Type Coordination Cages up to Three Nanometers in Size. Chem. Sci. 2017, 8, 1901– 1908, DOI: 10.1039/C6SC04732G[Crossref], [PubMed], [CAS], Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjsVyqsbo%253D&md5=de8545e2ece956ec7cd9addef19a1b6fPdII2L4-type coordination cages up to three nanometers in sizeJansze, Suzanne M.; Wise, Matthew D.; Vologzhanina, Anna V.; Scopelliti, Rosario; Severin, KayChemical Science (2017), 8 (3), 1901-1908CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The use of large ligands in coordination-based self-assembly represents an attractive strategy for the construction of supramol. assemblies more than two nanometers in size. However, the implementation of this strategy is hampered by the fact that the prepn. of such ligands often requires substantial synthetic effort. Herein, the authors describe a simple one-step protocol, which allows large bipyridyl ligands with a bent shape to be synthesized from easily accessible and/or com. available starting materials. The ligands were used to construct PdII2L4-type coordination cages of unprecedented size. Furthermore, the authors provide evidence that these cages may be stabilized by close intramol. packing of lipophilic ligand side chains. Packing effects of this kind are frequently encountered in protein assemblies, but they are seldom used as a design element in metallasupramol. chem.
- 7Sun, Q.-F.; Sato, S.; Fujita, M. An M18L24 Stellated Cuboctahedron through Post-Stellation of an M12L24 Core. Nat. Chem. 2012, 4, 330– 333, DOI: 10.1038/nchem.1285[Crossref], [PubMed], [CAS], Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1Whsb4%253D&md5=72a946106b40e8458bc08543404539f9An M18L24 stellated cuboctahedron through post-stellation of an M12L24 coreSun, Qing-Fu; Sato, Sota; Fujita, MakotoNature Chemistry (2012), 4 (4), 330-333CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)Platonic and Archimedean polyhedra, known to mathematicians, were recently constructed by chemists at a mol. scale by defining the vertexes and the edges with metal ions (M) and org. ligands (L), resp. Here, the authors report the 1st synthesis of a concave-surface 'stellated polyhedron', constructed by extending the faces of its precursor polyhedron until they intersect, forming addnl. nodes. The authors' approach involves the formation of an M12L24 cuboctahedron core, the linkers of which each bear a pendant ligand site that is subsequently able to bind an addnl. metal center to form the stellated M18L24 cuboctahedron. The [Pd12L124](BF4)24, [Pd12L124](PF6)24, [Pd18L124](BF4)36, [Pd18L224](CF3SO3)36 and [Pd18L224](NO3)36 complexes (L1 = 1,3-bis(pyridin-4-yl)-5-(pyridin-4-yloxymethyl)benzene, L2 = pyridin-4-ylmethyl 1,3-bis(pyridin-4-yl)benzoate) were prepd., and [Pd12L124](PF6)24 and [Pd18L224](CF3SO3)36 were characterized by x-ray crystallog. During this post-stellation process, the square faces of the M12L24 core are closed by coordination of the pendant moieties to the addnl. metal centers, but they are reopened on removing these metals ions from the vertexes. This behavior is reminiscent of the analogous metal-triggered gate opening-closing switches found in spherical virus capsids.
- 8Suzuki, K.; Sato, S.; Fujita, M. Template Synthesis of Precisely Monodisperse Silica Nanoparticles within Self-Assembled Organometallic Spheres. Nat. Chem. 2010, 2, 25– 29, DOI: 10.1038/nchem.446[Crossref], [PubMed], [CAS], Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFKns73O&md5=1ee470ffea0ef1e84d0dbddd295ccc5eTemplate synthesis of precisely monodisperse silica nanoparticles within self-assembled organometallic spheresSuzuki, Kosuke; Sato, Sota; Fujita, MakotoNature Chemistry (2010), 2 (1), 25-29CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)One of the key challenges in materials science is to control the size and shape of inorg. nanoparticles with a high degree of precision, as these parameters have a significant influence on the nanoparticles' properties and potential applications. Here, the authors describe the prepn. of highly monodisperse nanoparticles smaller than 5 nm in diam. by using self-assembled, hollow, spherical compds. as endo-templates'. These coordination complexes with pendant sugar groups lining their interiors-assembled from 12 metal ions and 24 bis-pyridyl ligands contg. substituents-acted as structurally well-defined templates for the sol-gel condensation of alkoxysilanes. The polydispersities of the nanoparticles made with this method approached unity, with Mw/Mn < 1.01. The component ligands are modified easily, which enables an accurate expansion of the coordination complex and the subsequent control of the monodisperse nanoparticles that span mol. wts. of 5,000 to 31,000 Da (corresponding to 2-4 nm in diam.). This method could be applicable to the prepn. of other inorg. nanoparticles.
- 9Yu, F.; Poole, D.; Mathew, S.; Yan, N.; Hessels, J.; Orth, N.; Ivanović-Burmazović, I.; Reek, J. N. H. Control over Electrochemical Water Oxidation Catalysis by Preorganization of Molecular Ruthenium Catalysts in Self-Assembled Nanospheres. Angew. Chem., Int. Ed. 2018, 57, 11247– 11251, DOI: 10.1002/anie.201805244[Crossref], [CAS], Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVWhurrE&md5=16242cf076c22371bbb95bbf2f826d7cControl over Electrochemical Water Oxidation Catalysis by Preorganization of Molecular Ruthenium Catalysts in Self-Assembled NanospheresYu, Fengshou; Poole, David III; Mathew, Simon; Yan, Ning; Hessels, Joeri; Orth, Nicole; Ivanovic-Burmazovic, Ivana; Reek, Joost N. H.Angewandte Chemie, International Edition (2018), 57 (35), 11247-11251CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Oxygen formation through water oxidn. catalysis is a key reaction in the context of fuel generation from renewable energies. The no. of homogeneous catalysts that catalyze water oxidn. at high rate with low overpotential is limited. Ruthenium complexes can be particularly active, esp. if they facilitate a dinuclear pathway for oxygen bond formation step. A supramol. encapsulation strategy is reported that involves preorganization of dil. solns. (10-5 M) of ruthenium complexes to yield high local catalyst concns. (up to 0.54 M). The preorganization strategy enhances the water oxidn. rate by two-orders of magnitude to 125 s-1, as it facilitates the diffusion-controlled rate-limiting dinuclear coupling step. Moreover, it modulates reaction rates, enabling comprehensive elucidation of electrocatalytic reaction mechanisms.
- 10Zhang, D.; Ronson, T. K.; Mosquera, J.; Martinez, A.; Guy, L.; Nitschke, J. R. Anion Binding in Water Drives Structural Adaptation in an Azaphosphatrane-Functionalized FeII4L4 Tetrahedron. J. Am. Chem. Soc. 2017, 139, 6574– 6577, DOI: 10.1021/jacs.7b02950[ACS Full Text], [CAS], Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntVGgsrc%253D&md5=b8bc86bec757f149e36de5c63e0bd457Anion Binding in Water Drives Structural Adaptation in an Azaphosphatrane-Functionalized FeII4L4 TetrahedronZhang, Dawei; Ronson, Tanya K.; Mosquera, Jesus; Martinez, Alexandre; Guy, Laure; Nitschke, Jonathan R.Journal of the American Chemical Society (2017), 139 (19), 6574-6577CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Anion-templated aq. self-assembly resulted in the formation of an endohedrally functionalized FeII4L4 tetrahedron from azaphosphatrane-based subcomponents. This new water-sol. cage is flexible and able to encapsulate anions with vols. ranging from 35 to 219 Å3 via hydrogen bonding and electrostatic interactions. It structurally adapts in response to the size and shape of the template anions, dynamically adopting a conformation either where all four azaphosphatrane +P-H vectors point inward, or else where one points outward and the other three inward. The two cage isomers can coexist in soln. and interconvert. A shape memory phenomenon was obsd. during guest displacement because guest exchange occurs more rapidly than structural reconfiguration.
- 11Custelcean, R.; Bonnesen, P. V.; Duncan, N. C.; Zhang, X.; Watson, L. A.; Van Berkel, G.; Parson, W. B.; Hay, B. P. Urea-Functionalised M4L6 Cage Receptors: Anion-Templated Self-Assembly and Selective Guest Exchange in Aqueous Solutions. J. Am. Chem. Soc. 2012, 134, 8525– 8534, DOI: 10.1021/ja300677w[ACS Full Text], [CAS], Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xmt1OqtLs%253D&md5=6339ecb163512efd336a38b60130615aUrea-Functionalized M4L6 Cage Receptors: Anion-Templated Self-Assembly and Selective Guest Exchange in Aqueous SolutionsCustelcean, Radu; Bonnesen, Peter V.; Duncan, Nathan C.; Zhang, Xiaohua; Watson, Lori A.; Van Berkel, Gary; Parson, Whitney B.; Hay, Benjamin P.Journal of the American Chemical Society (2012), 134 (20), 8525-8534CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors present an extensive study of a novel class of de novo designed tetrahedral M4L6 (M = Ni, Zn) cage receptors, wherein internal decoration of the cage cavities with urea anion-binding groups, via functionalization of the org. components L, led to selective encapsulation of tetrahedral oxoanions EO4n- (E = S, Se, Cr, Mo, W, n = 2; E = P, n = 3) from aq. solns., based on shape, size, and charge recognition. External functionalization with tBu groups led to enhanced soly. of the cages in aq. MeOH solns., thereby allowing for their thorough characterization by multinuclear (1H, 13C, 77Se) and diffusion NMR spectroscopies. Addnl. exptl. characterization by electrospray ionization mass spectrometry, UV-visible spectroscopy, and single-crystal x-ray diffraction, as well as theor. calcns., led to a detailed understanding of the cage structures, self-assembly, and anion encapsulation. The cage self-assembly is templated by EO4n- oxoanions (n ≥ 2), and upon removal of the templating anion the tetrahedral M4L6 cages rearrange into different coordination assemblies. The exchange selectivity among EO4n- oxoanions was studied with 77Se NMR spectroscopy using 77SeO42- as an anionic probe, which found the following selectivity trend: PO43- » CrO42- > SO42- > SeO42- > MoO42- > WO42-. In addn. to the complementarity and flexibility of the cage receptor, a combination of factors contribute to the obsd. anion selectivity, including the anions' charge, size, hydration, basicity, and H-bond acceptor abilities.
- 12Custelcean, R.; Bonnesen, P. V.; Roach, B. D.; Duncan, N. C. Ion-pair triple helicates and mesocates self-assembled from ditopic 2,2’-bipyridine-bis(urea) ligands and Ni(II) or Fe(II) sulfate salts. Chem. Commun. 2012, 48, 7438– 7440, DOI: 10.1039/c2cc33062h[Crossref], [PubMed], [CAS], Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XpsVOiuro%253D&md5=c2c79638bc33d7c1c02aa093a8edd60cIon-pair triple helicates and mesocates self-assembled from ditopic 2,2'-bipyridinebis(urea) ligands and Ni(II) or Fe(II) sulfate saltsCustelcean, Radu; Bonnesen, Peter V.; Roach, Benjamin D.; Duncan, Nathan C.Chemical Communications (Cambridge, United Kingdom) (2012), 48 (60), 7438-7440CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)NiSO4 and FeSO4 self-assemble with heteroditopic ligands (L) comprising 2,2'-bipyridine and o-phenylene-(bis)urea cation- and anion-binding sites, resp., into [ML3SO4] (M = Ni2+, Fe2+) triple-stranded ion-pair helicates and mesocates.
- 13Albrecht, M.; Isaak, E.; Baumert, M.; Gossen, V.; Raabe, G.; Fröhlich, R. Induced Fit” in Chiral Recognition: Epimerization upon Dimerization in the Hierarchical Self-Assembly of Helicate-Type Titanium(IV) Complexes. Angew. Chem., Int. Ed. 2011, 50, 2850– 2853, DOI: 10.1002/anie.201006448[Crossref], [CAS], Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXivVGhtrk%253D&md5=def95b0714e2842e4ebacf57fa09a550"Induced Fit" in Chiral Recognition: Epimerization upon Dimerization in the Hierarchical Self-Assembly of Helicate-type Titanium(IV) ComplexesAlbrecht, Markus; Isaak, Elisabeth; Baumert, Miriam; Gossen, Verena; Raabe, Gerhard; Froehlich, RolandAngewandte Chemie, International Edition (2011), 50 (12), 2850-2853, S2850/1-S2850/7CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Chiral esters (H2L) were prepd. from the reaction of 2,3-dihydroxybenzoic acid with (S)-citronellol and (S)-phenylethanol and form titanium tris(catecholates) Li2[TiL3] and Li[Li3{TiL3}2] which are characterized by CD spectra and in one case K[Li3{TiL3}2] by crystal structure anal. These complexes present a unique example of stereoinduction, in which the stereochem. at a labile metal complex unit is inverted and locked upon Li mediated dimerization. The stereocontrol can be explained by different conformations at the ester in the monomer and the dimer and is impressive in the context of dynamic chiral resoln. in a supramol. system following induced fit based on stereorecognition.
- 14Mal, P.; Breiner, B.; Rissanen, K.; Nitschke, J. R. White Phosphorus Is Air-Stable within a Self-Assembled Tetrahedral Capsule. Science 2009, 324, 1697– 1699, DOI: 10.1126/science.1175313[Crossref], [PubMed], [CAS], Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnsFOmsb0%253D&md5=bba55618442f24b69b6c10f462acab60White Phosphorus Is Air-Stable Within a Self-Assembled Tetrahedral CapsuleMal, Prasenjit; Breiner, Boris; Rissanen, Kari; Nitschke, Jonathan R.Science (Washington, DC, United States) (2009), 324 (5935), 1697-1699CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The air-sensitive nature of white phosphorus underlies its destructive effect as a munition; tetrahedral P4 mols. readily react with atm. dioxygen, leading this form of the element to spontaneously combust upon exposure to air. Here, hydrophobic P4 mols. are rendered air-stable and water-sol. within the hydrophobic hollows of self-assembled tetrahedral container mols., [Fe4L6]4- (L = 4,4'-bis(2-pyridylmethyleneamino)-1,1'-biphenyl-2,2'-disulfonate), which form in water from simple org. subcomponents and iron(II) ions. The host-guest complex with P4 was characterized by x-ray crystallog. This stabilization is not achieved through hermetic exclusion of O2 but rather by constriction of individual P4 mols.; the addn. of oxygen atoms to P4 would gave oxidized species too large for their containers. The phosphorus can be released in controlled fashion without disrupting the cage by adding the competing guest benzene.
- 15Cullen, W.; Misuraca, M. C.; Hunter, C. A.; Williams, N. H.; Ward, M. D. Highly Efficient Catalysis of the Kemp Elimination in the Cavity of a Cubic Coordination Cage. Nat. Chem. 2016, 8, 231– 236, DOI: 10.1038/nchem.2452[Crossref], [PubMed], [CAS], Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XislOlt74%253D&md5=4d3995ec0e5fd4bb58b826b6d9b5754dHighly efficient catalysis of the Kemp elimination in the cavity of a cubic coordination cageCullen, William; Misuraca, M. Cristina; Hunter, Christopher A.; Williams, Nicholas H.; Ward, Michael D.Nature Chemistry (2016), 8 (3), 231-236CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)The hollow cavities of coordination cages can provide an environment for enzyme-like catalytic reactions of small-mol. guests. Here, we report a new example (catalysis of the Kemp elimination reaction of benzisoxazole with hydroxide to form 2-cyanophenolate) in the cavity of a water-sol. M8L12 coordination cage, with two features of particular interest. First, the rate enhancement is among the largest obsd. to date: at pD 8.5, the value of kcat/kuncat is 2 × 105, due to the accumulation of a high concn. of partially desolvated hydroxide ions around the bound guest arising from ion-pairing with the 16+ cage. Second, the catalysis is based on two orthogonal interactions: (1) hydrophobic binding of benzisoxazole in the cavity and (2) polar binding of hydroxide ions to sites on the cage surface, both of which were established by competition expts.
- 16Murase, T.; Nishijima, Y.; Fujita, M. Cage-Catalyzed Knoevenagel Condensation under Neutral Conditions in Water. J. Am. Chem. Soc. 2012, 134, 162– 164, DOI: 10.1021/ja210068f[ACS Full Text], [CAS], Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFyltbbP&md5=0f5a9c3aff795de3709a9d5f580cb65fCage-Catalyzed Knoevenagel Condensation under Neutral Conditions in WaterMurase, Takashi; Nishijima, Yuki; Fujita, MakotoJournal of the American Chemical Society (2012), 134 (1), 162-164CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A cationic coordination cage dramatically accelerates the Knoevenagel condensation of arom. aldehydes in water under neutral conditions. The addn. of a nucleophile to the aldehyde to generate anionic intermediates seems to be facilitated by the cationic environment of the cavity. The products, e.g. I, are ejected from the cage as a result of the host-guest size discrepancy. As a result, the condensation is promoted by a catalytic amt. of the cage.
- 17Rizzuto, F. J.; Pröhm, P.; Plajer, A. J.; Greenfield, J. L.; Nitschke, J. R. Hydrogen-Bond-Assisted Symmetry Breaking in a Network of Chiral Metal–Organic Assemblies. J. Am. Chem. Soc. 2019, 141, 1707– 1715, DOI: 10.1021/jacs.8b12323[ACS Full Text], [CAS], Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkslOrtg%253D%253D&md5=24a60b5dfdfb0c3299ddf6aff861a4d4Hydrogen-Bond-Assisted Symmetry Breaking in a Network of Chiral Metal-Organic AssembliesRizzuto, Felix J.; Prohm, Patrick; Plajer, Alex J.; Greenfield, Jake L.; Nitschke, Jonathan R.Journal of the American Chemical Society (2019), 141 (4), 1707-1715CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Herein the authors elucidate the interplay of chiral, chelate, solvent, and hydrogen-bonding information in the self-assembly of a series of new three-dimensional metal-org. architectures. Enantiopure ligands, each contg. H-bond donors and acceptors, form different structures, depending on the ratio in which they are combined: enantiopure components form M4L4 assemblies, whereas racemic mixts. form M3L3 stacks. Chiral amplification within M3L3 enantiomers was obsd. when a 2:1 ratio of R and S subcomponent enantiomers was employed. Simply switching the solvent (from MeCN to MeOH) or chelating unit (from bidentate to tridentate) increased the diversity of structures that can be generated from these building blocks, leading to the selective formation of novel M2L2 and M3L2 assemblies. The addn. of achiral ligand building blocks gave further structures: When an achiral subcomponent was combined with its R and S chiral congeners, a three-layer heteroleptic architecture was generated, with the achiral unit sitting at the top of the stack. When combined with the S enantiomer only, however, the achiral unit assembled in the center of the structure, thus demonstrating the selective placement of achiral units within chiral systems. Further sorting expts. revealed that combining R and S stereocenters within a single ligand led to diastereoselective product generation. These results show how geometric complementarity between different ligands impacts upon the degree of hydrogen-bonding within the assembly, stabilizing specific low-symmetry architectures from among many possible structural outcomes.
- 18Song, B.; Kandapal, S.; Gu, J.; Zhang, K.; Reese, A.; Ying, Y.; Wang, L.; Wang, H.; Li, Y.; Wang, M.; Lu, S.; Hao, X.-Q.; Li, X.; Xu, B.; Li, X. Self-Assembly of Polycyclic Supramolecules Using Linear Metal-Organic Ligands. Nat. Commun. 2018, 9, 4575, DOI: 10.1038/s41467-018-07045-9[Crossref], [PubMed], [CAS], Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3cvlslKkug%253D%253D&md5=f0139e943db88ab2c277b93f1c270d87Self-assembly of polycyclic supramolecules using linear metal-organic ligandsSong Bo; Wang Lei; Wang Heng; Li Yiming; Li Xiaopeng; Kandapal Sneha; Zhang Keren; Reese Alex; Xu Bingqian; Gu Jiali; Li Xiaohong; Ying Yuanfang; Wang Ming; Lu Shuai; Hao Xin-QiNature communications (2018), 9 (1), 4575 ISSN:.Coordination-driven self-assembly as a bottom-up approach has witnessed a rapid growth in building giant structures in the past few decades. Challenges still remain, however, within the construction of giant architectures in terms of high efficiency and complexity from simple building blocks. Inspired by the features of DNA and protein, which both have specific sequences, we herein design a series of linear building blocks with specific sequences through the coordination between terpyridine ligands and Ru(II). Different generations of polycyclic supramolecules (C1 to C5) with increasing complexity are obtained through the self-assembly with Cd(II), Fe(II) or Zn(II). The assembled structures are characterized via multi-dimensional mass spectrometry analysis as well as multi-dimensional and multinuclear NMR ((1)H, COSY, NOESY) analysis. Moreover, the largest two cycles C4 and C5 hierarchically assemble into ordered nanoscale structures on a graphite based on their precisely-controlled shapes and sizes with high shape-persistence.
- 19Hasenknopf, B.; Lehn, J.-M.; Boumediene, N.; Dupont-Gervais, A.; Van Dorsselaer, A.; Kneisel, B.; Fenske, D. Self-Assembly of Tetra- and Hexanuclear Circular Helicates. J. Am. Chem. Soc. 1997, 119, 10956– 10962, DOI: 10.1021/ja971204r[ACS Full Text], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXnt1Ohur0%253D&md5=c9ac3a9917463f3cbe31ebe5adfa1488Self-Assembly of Tetra- and Hexanuclear Circular HelicatesHasenknopf, Bernold; Lehn, Jean-Marie; Boumediene, Nedjia; Dupont-Gervais, Annick; Van Dorsselaer, Alain; Kneisel, Boris; Fenske, DieterJournal of the American Chemical Society (1997), 119 (45), 10956-10962CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The self-assembly of the tris-bipyridine ligands BI (5,5'-bis[2-(5'-methyl-2,2'-bipyridin-5-yl)ethyl]2,2'-bipyridine) and BII (5,5'-bis[(5'-methyl-2,2'-bipyridin-5-yl)methoxymethyl]2,2'-bipyridine) with iron(II) salts yields polynuclear complexes displaying structures of cyclic double-helix type, termed circular helicates [n]cH (of order n). With BI, in which the bipyridine units in the ligand are connected by ethylene bridges, penta- or hexanuclear architectures [5]cH ([Fe5BI5]10+) and [6]cH ([Fe6BI6]12+) were obtained, depending on the anion present during the self-assembly process. The elongated tris-bipyridine ligand BII with oxypropylene bridges forms a tetranuclear circular helicate [4]cH ([Fe4BII4](PF6)8), whose structure was confirmed by crystal structure detn. as a solvate (tetragonal, space group P4/n, R1 = 0.1178). The possible oligomeric combinations of tris-bipy ligands and iron(II) ions may be considered to constitute the potential members of a virtual combinatorial library, generated via dynamic combinatorial chem., from which a specific real constituent of the virtual set of circular helicates is expressed in given conditions.
- 20Hasenknopf, B.; Lehn, J.-M.; Kneisel, B. O.; Baum, G.; Fenske, D. Self-Assembly of a Circular Double Helicate. Angew. Chem., Int. Ed. 1996, 35, 1838– 1840, DOI: 10.1002/anie.199618381[Crossref], [CAS], Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xls1Gqtbo%253D&md5=5a9015849f62c0b55a27db4d6c724bb3Self-assembly of a circular double helicateHasenknopf, Bernold; Lehn, Jean-Marie; Kneisel, Boris O.; Baum, Gerhard; Fenske, DieterAngewandte Chemie, International Edition in English (1996), 35 (16), 1838-1840CODEN: ACIEAY; ISSN:0570-0833. (VCH)Reaction of tris(bipyridyl) ligand I (L) with 1 equiv FeCl2 in ethylene glycol at 170°, followed by addn. of NH4PF6, afforded a red solid analyzed as [(Fe5L5)Cl](PF6)9 (1H NMR, ESI-MS, IR, UV-visible spectra). The crystal structure of [{(Fe5L5)Cl}2](PF6)17.5Cl0.5·11MeNO2·40.5H2O was detd. by x-ray crystallog. (monoclinic, space group P2/n). The [Fe5L5]10+ cation may be described as a circular double helix resulting in a torus which is a specific receptor of chloride ion, as evidenced by its strong binding to Cl-. The salt of the chiral cation is obtained as a racemic mixt.; full resoln. of the two enantiomers was not achieved. The [Fe5L5Cl]9+ cation is presented as a combinatorial generation of a receptor by self-assembly of a set of components into an entity that most strongly binds the substrate. In other words, the cations pentameric cyclic structure is selected among all possible oligomers when chloride ions are present; other entities may be formed with other anions.
- 21Hasenknopf, B.; Lehn, J.-M.; Boumediene, N.; Leize, E.; Van Dorsselaer, A. Kinetic and Thermodynamic Control in Self-Assembly: Sequential Formation of Linear and Circular Helicates. Angew. Chem., Int. Ed. 1998, 37, 3265– 3268, DOI: 10.1002/(SICI)1521-3773(19981217)37:23<3265::AID-ANIE3265>3.0.CO;2-B[Crossref], [CAS], Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksVejsw%253D%253D&md5=f44150612b7820b40fcd51c0181dc62eKinetic and thermodynamic control in self-assembly: sequential formation of linear and circular helicatesHasenknopf, Bernold; Lehn, Jean-Marie; Boumediene, Nedjia; Leize, Emmanuelle; Van Dorsselaer, AlainAngewandte Chemie, International Edition (1998), 37 (23), 3265-3268CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The self-assembly process for the formation of linear and circular helicates was studied in order to det. the structural, mechanistic and physicochem. factors affecting the formation process. The reaction of the tris(bipyridine) ligand L (L = I) with FeCl2 or NiCl2 is shown to first form a linear triple helicate complex [M3L3]6- (M = Fe, Ni) which upon continued heating transforms to a circular helicate complex [M5L5]9-. The linear helicate structure the kinetically favored product.
- 22Cullen, W.; Metherell, A. J.; Wragg, A. B.; Taylor, C. G. P.; Williams, N. H.; Ward, M. D. Catalysis in a Cationic Coordination Cage Using a Cavity-Bound Guest and Surface-Bound Anions: Inhibition, Activation, and Autocatalysis. J. Am. Chem. Soc. 2018, 140, 2821– 2828, DOI: 10.1021/jacs.7b11334[ACS Full Text], [CAS], Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitl2mur0%253D&md5=6688f27c05075b2cf9bea7b548692a47Catalysis in a Cationic Coordination Cage Using a Cavity-Bound Guest and Surface-Bound Anions: Inhibition, Activation, and AutocatalysisCullen, William; Metherell, Alexander J.; Wragg, Ashley B.; Taylor, Christopher G. P.; Williams, Nicholas H.; Ward, Michael D.Journal of the American Chemical Society (2018), 140 (8), 2821-2828CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The Kemp elimination (reaction of benzisoxazole with base to give 2-cyanophenolate) is catalyzed in the cavity of a cubic M8L12 coordination cage because of a combination of (i) benzisoxazole binding in the cage cavity driven by the hydrophobic effect, and (ii) accumulation of hydroxide ions around the 16+ cage surface driven by ion-pairing. Here we show how reaction of the cavity-bound guest is modified by the presence of other anions which can also accumulate around the cage surface and displace hydroxide, inhibiting catalysis of the cage-based reaction. Addn. of chloride or fluoride inhibits the reaction with hydroxide to the extent that a new autocatalytic pathway becomes apparent, resulting in a sigmoidal reaction profile. In this pathway the product 2-cyanophenolate itself accumulates around the cationic cage surface, acting as the base for the next reaction cycle. The affinity of different anions for the cage surface is therefore 2-cyanophenolate (generating autocatalysis) > chloride > fluoride (which both inhibit the reaction with hydroxide but cannot deprotonate the benzisoxazole guest) > hydroxide (default reaction pathway). The presence of this autocatalytic pathway demonstrates that a reaction of a cavity-bound guest can be induced with different anions around the cage surface in a controllable way; this was confirmed by adding different phenolates to the reaction, which accelerate the Kemp elimination to different extents depending on their basicity. This represents a significant step toward the goal of using the cage as a catalyst for bimol. reactions between a cavity-bound guest and anions accumulated around the surface.
- 23Tidmarsh, I. S.; Faust, T. B.; Adams, H.; Harding, L. P.; Russo, L.; Clegg, W.; Ward, M. D. Octanuclear Cubic Coordination Cages. J. Am. Chem. Soc. 2008, 130, 15167– 15175, DOI: 10.1021/ja805605y[ACS Full Text], [CAS], Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1CgtrzP&md5=22025ec0c52f6468fdf66fe8d04726b8Octanuclear Cubic Coordination CagesTidmarsh, Ian S.; Faust, Thomas B.; Adams, Harry; Harding, Lindsay P.; Russo, Luca; Clegg, William; Ward, Michael D.Journal of the American Chemical Society (2008), 130 (45), 15167-15175CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two new bis-bidentate bridging ligands were prepd., Lnaph and Lanth, 1,5-bis(3-(pyridin-2-yl)-pyrazol-1-ylmethyl)naphthalene and 9,10-bis(3-(pyridin-2-yl)-pyrazol-1-ylmethyl)anthracene, resp., which contain two chelating pyrazolyl-pyridine units connected to an arom. spacer (naphthalene-1,5-diyl and anthracene-9,10-diyl, resp.) via methylene connectors. Each of these reacts with transition metal dications having a preference for octahedral coordination geometry to afford {M8L12}16+ cages (for Lanth, M = Cu, Zn; for Lnaph, M = Co, Ni, Cd) which have an approx. cubic arrangement of metal ions with a bridging ligand spanning each of the twelve edges, and a large central cavity contg. a mixt. of anions and/or solvent mols. The cages based on Lanth have two cyclic helical {M4L4} faces, of opposite chirality, connected by four addnl. Lanth ligands as pillars; all metal centers have a meridional tris-chelate configuration. In contrast the cages based on Lnaph have (noncrystallog.) S6 symmetry, with a diagonally opposite pair of corners having a facial tris-chelate configuration with the other six being meridional. An addnl. significant difference between the two types of structure is that the cubes contg. Lanth do not show significant interligand arom. stacking interactions. However, in the cages based on Lnaph, there are six five-membered stacks of arom. ligand fragments around the periphery, each based on an alternating array of electron-rich (naphthyl) and electron-deficient (pyrazolyl-pyridine, coordinated to M2+) arom. units. A consequence of this is that the cages {M8(Lnaph)12}16+ retain their structural integrity in polar solvents, in contrast to the cages {M8(Lanth)12}16+ which dissoc. in polar solvents. Consequently, the cages {M8(Lnaph)12}16+ give NMR spectra in agreement with the symmetry obsd. in the solid state, and their fluorescence spectra (for M = Cd) display (in addn. to the normal naphthalene-based π-π* fluorescence) a lower-energy exciplex-like emission feature assocd. with a naphthyl → pyrazolyl-pyridine charge-transfer excited state arising from the π-stacking between ligands around the cage periphery.
- 24Ayme, J.-F.; Beves, J. E.; Leigh, D. A.; McBurney, R. T.; Rissanen, K.; Schultz, D. A Synthetic Molecular Pentafoil Knot. Nat. Chem. 2012, 4, 15– 20, DOI: 10.1038/nchem.1193[Crossref], [CAS], Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVagurzM&md5=34ca462ac92cab02fdcd542e617f5f04A synthetic molecular pentafoil knotAyme, Jean-Francois; Beves, Jonathon E.; Leigh, David A.; McBurney, Roy T.; Rissanen, Kari; Schultz, DavidNature Chemistry (2012), 4 (1), 15-20CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)Knots are being discovered with increasing frequency in both biol. and synthetic macromols. and have been fundamental topol. targets for chem. synthesis for the past two decades. Here, we report on the synthesis of the most complex non-DNA mol. knot prepd. to date: the self-assembly of five bis-aldehyde and five bis-amine building blocks about five metal cations and one chloride anion to form a 160-atom-loop mol. pentafoil knot (five crossing points). The structure and topol. of the knot is established by NMR spectroscopy, mass spectrometry and X-ray crystallog., revealing a sym. closed-loop double helicate with the chloride anion held at the center of the pentafoil knot by ten CH···Cl- hydrogen bonds. The one-pot self-assembly reaction features an exceptional no. of different design elements-some well precedented and others less well known within the context of directing the formation of (supra)mol. species. We anticipate that the strategies and tactics used here can be applied to the rational synthesis of other higher-order interlocked mol. architectures.
- 25Danon, J. J.; Krüger, A.; Leigh, D. A.; Lemonnier, J.-F.; Stephens, A. J.; Vitorica-Yrezabal, I. J.; Woltering, S. L. Braiding a Molecular Knot with Eight Crossings. Science 2017, 355, 159– 162, DOI: 10.1126/science.aal1619[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXms12jtQ%253D%253D&md5=eb89310ee73f9bfbcc9278eecf1131edBraiding a molecular knot with eight crossingsDanon, Jonathan J.; Krueger, Anneke; Leigh, David A.; Lemonnier, Jean-Francois; Stephens, Alexander J.; Vitorica-Yrezabal, Inigo J.; Woltering, Steffen L.Science (Washington, DC, United States) (2017), 355 (6321), 159-162CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Knots may ultimately prove just as versatile and useful at the nanoscale as at the macroscale. However, the lack of synthetic routes to all but the simplest mol. knots currently prevents systematic investigation of the influence of knotting at the mol. level. We found that it is possible to assemble four building blocks into three braided ligand strands. Octahedral iron(II) ions control the relative positions of the three strands at each crossing point in a circular triple helicate, while structural constraints on the ligands det. the braiding connections. This approach enables two-step assembly of a mol. 819 knot (I) featuring eight nonalternating crossings in a 192-atom closed loop ∼20 nm in length. The resolved metal-free 819 knot enantiomers have pronounced features in their CD spectra resulting solely from topol. chirality.
- 26Buchard, A.; Kember, M. R.; Sandeman, K. G.; Williams, C. K. A Bimetallic Iron(III) Catalyst for CO2/Epoxide Coupling. Chem. Commun. 2011, 47, 212– 214, DOI: 10.1039/C0CC02205E[Crossref], [PubMed], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFeqtLnP&md5=6666bad91bcac2c833a7fdc342ffab3eA bimetallic iron(III) catalyst for CO2/epoxide couplingBuchard, Antoine; Kember, Michael R.; Sandeman, Karl G.; Williams, Charlotte K.Chemical Communications (Cambridge, United Kingdom) (2011), 47 (1), 212-214CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A novel di-iron(III) catalyst for the copolymn. of cyclohexene oxide and CO2 to yield poly(cyclohexene carbonate), under mild conditions, is reported. The catalyst selectivity was completely changed on addn. of an ammonium co-catalyst to yield only the cis-isomer of the cyclic carbonate, also under mild conditions. Addnl., the catalyst was active for propylene carbonate and styrene carbonate prodn. at 1 atm pressure.
- 27Desai, S. P.; Ye, J.; Zheng, J.; Ferrandon, M. S.; Webber, T. E.; Platero-Prats, A. E.; Duan, J.; Garcia-Holley, P.; Camaioni, D. M.; Chapman, K. W.; Delferro, M.; Farha, O. K.; Fulton, J. L.; Gagliardi, L.; Lercher, J. A.; Penn, R. L.; Stein, A.; Lu, C. C. Well-Defined Rhodium–Gallium Catalytic Sites in a Metal–Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-Alkenes. J. Am. Chem. Soc. 2018, 140, 15309– 15318, DOI: 10.1021/jacs.8b08550[ACS Full Text], [CAS], Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvF2mtLnN&md5=3e0d65df531f54b47d4a3ffbe1af14d9Well-Defined Rhodium-Gallium Catalytic Sites in a Metal-Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-AlkenesDesai, Sai Puneet; Ye, Jingyun; Zheng, Jian; Ferrandon, Magali S.; Webber, Thomas E.; Platero-Prats, Ana E.; Duan, Jiaxin; Garcia-Holley, Paula; Camaioni, Donald M.; Chapman, Karena W.; Delferro, Massimiliano; Farha, Omar K.; Fulton, John L.; Gagliardi, Laura; Lercher, Johannes A.; Penn, R. Lee; Stein, Andreas; Lu, Connie C.Journal of the American Chemical Society (2018), 140 (45), 15309-15318CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-org. framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.
- 28Artem’ev, A. V.; Bagryanskaya, I. Y.; Doronina, E. P.; Tolstoy, P. M.; Gushchin, A. L.; Rakhmanova, M. I.; Ivanov, A. Y.; Suturina, A. O. A New Family of Clusters Containing a Silver-Centered Tetracapped [[email protected]4(μ3-P)4] Tetrahedron, Inscribed within a N12 Icosahedron. Dalton. Trans. 2017, 46, 12425– 12429, DOI: 10.1039/C7DT02597A[Crossref], [PubMed], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVersL3L&md5=82a696ba162e230691fbd57682f44e83A new family of clusters containing a silver-centered tetracapped [[email protected](μ3-P)4] tetrahedron, inscribed within a N12 icosahedronArtem'ev, Alexander V.; Bagryanskaya, Irina Yu.; Doronina, Evgeniya P.; Tolstoy, Peter M.; Gushchin, Artem L.; Rakhmanova, Mariana I.; Ivanov, Alexander Yu.; Suturina, Anastasiya O.Dalton Transactions (2017), 46 (37), 12425-12429CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)An unprecedented silver-centered P-tetracapped [[email protected](μ3-P)4] tetrahedron inscribed within a N12 icosahedral cage was discovered in the novel family of luminescent clusters. The latter are easily self-assembled by reacting AgI salts with tris(2-pyridyl)phosphine (Py3P).
- 29Schenck, T. G.; Downes, J. M.; Milne, C. R. C.; Mackenzie, P. B.; Boucher, T. G.; Whelan, J.; Bosnich, B. Bimetallic Reactivity. Synthesis of Bimetallic Complexes Containing a Bis(Phosphino)Pyrazole Ligand. Inorg. Chem. 1985, 24, 2334– 2337, DOI: 10.1021/ic00209a003[ACS Full Text], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXksVOiu7o%253D&md5=d8541baf671448994adb2dcd8331af1fBimetallic reactivity. Synthesis of bimetallic complexes containing a bis(phosphino)pyrazole ligandSchenck, Terry G.; Downes, J. M.; Milne, C. R. C.; Mackenzie, Peter B.; Boucher, Terry G.; Whelan, John; Bosnich, B.Inorganic Chemistry (1985), 24 (15), 2334-7CODEN: INOCAJ; ISSN:0020-1669.3,5-Bis(diphenylphosphinomethyl)pyrazole (PNNHP), which was prepd., has a geometry that provides for 2 metals to reside within cooperative distance but does not allow for metal-metal bond formation. The following planar bimetallic complexes with and without anionic bridging groups (X) were isolated and characterized: [M2(PNNP)(X)L2] (M = Pd(II), X = Cl, L = Cl; M = Rh(I), X = Cl and PPh2, L = CO; M = Ir(I), X = PPh2, L = CO) and [M2(PNNP)L4]+ (M = Pd(II), 2L = π-allyl; M = Rh(I) and Ir(I), 2L = diene and L = CO) resp.
- 30Sowa, T.; Kawamura, T.; Shida, T.; Yonezawa, T. Electronic Structure of the Rhodium-Rhodium Bond in Dirhodium Tetracarboxylates by a Study of Electronic Spectra of Neutral Molecules and Their Cation Radicals. Inorg. Chem. 1983, 22, 56– 61, DOI: 10.1021/ic00143a014[ACS Full Text], [CAS], Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXisV2nsg%253D%253D&md5=c28ea93d688070d407a03dd7eb1ffde0Electronic structure of the rhodium-rhodium bond in dirhodium tetracarboxylates by a study of electronic spectra of neutral molecules and their cation radicalsSowa, Takayoshi; Kawamura, Takashi; Shida, Tadamasa; Yonezawa, TeijiroInorganic Chemistry (1983), 22 (1), 56-61CODEN: INOCAJ; ISSN:0020-1669.Electronic absorption spectra of Rh2(O2CR)4L2 [R = Et, CF3; L = H2O, HC(CH2CH2)3N, PPh3, P(c-C6H11)3, P(OPh)3, P(OMe)3] and some of their cation radicals were examd. The intense absorption band in the near-UV region (~ν = (25-46) × 103 cm-1 and log ε = 4.0-4.7 for neutral complexes and ~ν = (17-23) × 103 cm-1 and log ε = 4.0-4.3 for cationic complexes) is assigned to the intermetallic σ → σ* transition. Ligand dependences of the transition energy and the intensity of this absorption band were interpreted with a bonding model constructed from a hypothesis that metal-ligand interactions are larger than intermetallic interactions. This valence model can also account qual. for the ligand dependences of the intermetallic bond distance and the stretching frequency of the intermetallic bond in dirhodium tetracarboxylates and the odd-electron distribution in their cation radicals. The odd electron of Rh2(O2CMe)4(H2O)2+· is probably not accommodated in the σRhRh MO. The CO stretching frequency of Rh2(O2CCF3)4(CO)2 is 7 cm-1 higher than that of the free CO, showing that there is practically no π-type interactions between the metal and the carbonyl in this complex.
- 31Bera, J. K.; Sadhukhan, N.; Majumdar, M. 1,8-Naphthyridine Revisited: Applications in Dimetal Chemistry. Eur. J. Inorg. Chem. 2009, 27, 4023– 4038, DOI: 10.1002/ejic.200900312
- 32Giordana, A.; Priola, E.; Bonometti, E.; Benzi, P.; Operti, L.; Diana, E. Structural and Spectroscopic Study of the Asymmetric 2-(2′-Pyridyl)-1,8-Naphthyridine Ligand with Closed-Shell Metals. Polyhedron 2017, 138, 239– 248, DOI: 10.1016/j.poly.2017.09.032[Crossref], [CAS], Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFylu7rL&md5=eee1cdecdb3cdcaecf7edbcf20e54806Structural and spectroscopic study of the asymmetric 2-(2'-pyridyl)-1,8-naphthyridine ligand with closed-shell metalsGiordana, Alessia; Priola, Emanuele; Bonometti, Elisabetta; Benzi, Paola; Operti, Lorenza; Diana, ElianoPolyhedron (2017), 138 (), 239-248CODEN: PLYHDE; ISSN:0277-5387. (Elsevier Ltd.)Herein, the authors report the synthesis and characterization of a series of complexes of the asym. ligand 2-(2'-pyridyl)-1,8-naphthyridine (pyNP, 1) with different closed-shell metals. For the first time ligand pyNP has been structurally and vibrationally characterized. The geometry of the pyNP ligand, with 3 N donor sites, can favor metallophilic interaction in complexes, so the authors performed a study on its coordination chem. with different metals (Ag(I), Hg(II) and Pb(II)). Twelve new complexes, namely [Ag2(pyNP)2(NO3)2] (2), [Hg(pyNP)X2](X = Cl(3), Br(4), I(5), CN(6), SCN(7, 8)), [Pb(pyNP)2(NO3)2] (9), [Pb(pyNP)(NO3)2]2 (10), [Cu(pyNP)Cl2(H2O)] (11), [Cu(pyNP)2(H2O)][Hg2(CN)4Cl2]-H2O (12) and [Cu(pyNP)(H2O)2(μ-CN)Hg2(CN)3Cl2]-H2O (13), have been synthesized and characterized by single crystal x-ray diffraction, Raman, FTIR and electronic spectroscopies. Structure of complex 2 shows a supported argentophilic interaction, and is the first structure in which pyNP bonds two previously unbounded metal centers.
- 33Dong, Y.-B.; Geng, Y.; Ma, J.-P.; Huang, R.-Q. Organometallic Silver(I) Supramolecular Complexes Generated from Multidentate Furan-Containing Symmetric and Unsymmetric Fulvene Ligands and Silver(I) Salts. Inorg. Chem. 2005, 44, 1693– 1703, DOI: 10.1021/ic048518h[ACS Full Text], [CAS], Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXovFSrtA%253D%253D&md5=7dc712f0155ff64706e2bd2c3264b35cOrganometallic Silver(I) Supramolecular Complexes Generated from Multidentate Furan-Containing Symmetric and Unsymmetric Fulvene Ligands and Silver(I) SaltsDong, Yu-Bin; Geng, Yan; Ma, Jian-Ping; Huang, Ru-QiInorganic Chemistry (2005), 44 (6), 1693-1703CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)One new conjugated sym. fulvene ligand L1 (I, R = 2-furyl) and two new unsym. fulvene ligands L2 and L3 (I, R = 4- and 3-cyanophenyl, resp.) were synthesized. Five new supramol. complexes, Ag2(L1)3(SO3CF3)3 (1, monoclinic, space group P21/c; a 12.702(3), b 26.118(7), c 13.998(4) Å, β 96.063(4)°, Z = 4), [Ag(L1)]ClO4 (2, monoclinic, space group C2/c; a 17.363(2), b 13.2794(18), c 13.4884(18) Å, β 100.292(2)°, Z = 8), [Ag(L1)(C6H6)SbF6]·0.5C6H6·H2O (3, monoclinic, P21/c; a 6.8839(11), b 20.242(3), c 18.934(3) Å, β 91.994(3)°, Z = 4), Ag(L2)(SO3CF3) (4, triclinic, P‾1; a 8.629(3), b 10.915(3), c 11.178(3) Å, α 100.978(4), β 91.994(3), γ 105.652(4)°, Z = 2), and Ag(L3)(H2O)(SO3CF3) (5, triclinic, P‾1; a 8.914(5), b 10.809(6), c 11.283(6) Å, α 69.255(8), β 87.163(9), γ 84.993(8)°, Z = 2) were obtained through self-assembly based on these three new fulvene ligands in a benzene/toluene mixed-solvent system. Compds. 1-5 were fully characterized by IR spectroscopy, elemental anal., and single-crystal x-ray diffraction. The coordination chem. of new fulvene ligands is versatile. They can adopt either cis- or trans-conformation to bind soft acid Ag(I) ion through not only the terminal -CN and furan functional groups but also the fulvene carbon atoms into organometallic coordination polymers or discrete complexes. The luminescent properties of L1-L3 and their Ag(I) complexes were studied preliminarily in EtOH and solid state.
- 34Yue, N. L. S.; Jennings, M. C.; Puddephatt, R. J. Disilver(I) Macrocycles: Variation of Cavity Size with Anion Binding. Inorg. Chem. 2005, 44, 1125– 1131, DOI: 10.1021/ic048549c[ACS Full Text], [CAS], Google Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmsVWisA%253D%253D&md5=dbb464b2bb9c55f221e65962ca4c2118Disilver(I) Macrocycles: Variation of Cavity Size with Anion BindingYue, Nancy L. S.; Jennings, Michael C.; Puddephatt, Richard J.Inorganic Chemistry (2005), 44 (4), 1125-1131CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Reaction of the N-methylated bis(amidopyridine) ligand, LL = C6H4(1,3-CONMe-4-C5H4N)2, with AgNO3, AgO2CCF3, AgO3SCF3, AgBF4, and AgPF6 gave the corresponding cationic disilver(I) macrocycles [Ag2(μ-LL)2]X2, 2a-e, resp. The transannular Ag···silver distance in the macrocycles varies greatly from 2.99 to 7.03 Å, and these differences arise through a combination of different modes of anion binding and from the presence or absence of Ag···silver secondary bonding. In all complexes, the ligand adopts a conformation in which the Me group and O atom of the MeNCO units are mutually cis, but the overall macrocycle can exist in either boat (X = PF6 only) or chair conformation. Short transannular Ag···silver distances are found in complexes 2b,c, in which the anions CF3CO2- and CF3SO3- bind above and below the macrocycle, but longer Ag···silver distances are found for 2a,d,e, in which the anions are present, at least in part, inside the disilver macrocycle. Easy anion exchange occurs in soln., and studies using ESI-MS indicate that the anion binding to form [Ag2X(μ-LL)2]+ follows the sequence X = CF3CO2- > NO3- > CF3SO3-.
- 35Beauchamp, D. A.; Loeb, S. J. Molecular Squares, Rectangles and Infinite Helical Chains Utilising the Simple ‘Corner’ Ligand 4-(2-Pyridyl)-Pyrimidine. Chem. Commun. 2002, 2484– 2485, DOI: 10.1039/B206989J[Crossref], [CAS], Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotVylsr0%253D&md5=0911c2c4fba33b3bf73c31a774a023e0Molecular squares, rectangles and infinite helical chains utilising the simple corner' ligand 4-(2-pyridyl)pyrimidineBeauchamp, Derek A.; Loeb, Stephen J.Chemical Communications (Cambridge, United Kingdom) (2002), (21), 2484-2485CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The ligand 4-(2-pyridyl)pyrimidine (L) forms multinuclear Ag(I) complexes, {[AgL]X}4 (X = BF4, triflate) and {[AgL]NO3}n by a combination of chelating and bridging coordination modes. Mol. shape (square or rectangle) and degree of aggregation depend on the anion used. In {[AgL]BF4}4 (triclinic, space group P‾1, Z = 1, R1 = 0.0712, wR1 = 0.0724) each Ag is pseudo-trigonal. In {[AgL]O3SCF3}4 (triclinic, space group P‾1, Z = 1, R1 = 0.0279, wR1 = 0.0299) the complex cation is rectangular with 2 Ag atoms 2-coordinate and 2 Ag atoms tetrahedral. In {[AgL]NO3}n (monoclinic, space group P21/n, Z = 4, R1 = 0.0279, wR1 = 0.0299) the Ag atoms are coordinated by the bidentate L and NO3- in an infinite chain.
- 36Wiley, C. A.; Holloway, L. R.; Miller, T. F.; Lyon, Y.; Julian, R. R.; Hooley, R. J. Electronic Effects on Narcissistic Self-Sorting in Multicomponent Self-Assembly of Fe-Iminopyridine Meso-Helicates. Inorg. Chem. 2016, 55, 9805– 9815, DOI: 10.1021/acs.inorgchem.6b01644[ACS Full Text], [CAS], Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2iu7nL&md5=57b3a5d49525f0436fea780533d6abd6Electronic Effects on Narcissistic Self-Sorting in Multicomponent Self-Assembly of Fe-Iminopyridine meso-HelicatesWiley, Calvin A.; Holloway, Lauren R.; Miller, Tabitha F.; Lyon, Yana; Julian, Ryan. R.; Hooley, Richard J.Inorganic Chemistry (2016), 55 (19), 9805-9815CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Small changes in the electron donating ability of coordinating groups have substantial effects on the multicomponent self-assembly of Fe(II)-iminopyridine-based meso-helicate complexes. Both the nature of the internal diamine core and the terminal formylpyridine reactants control the rate of the assembly process, the thermodn. favorability of the meso-helicate products, and the selective incorporation of different aldehyde termini into the assembly. Steric congestion at the coordinating ligands can prevent assembly altogether, and favorable incorporation of electron-rich aldehyde termini is obsd., even though the rate of reaction is accelerated using electron-poor aldehyde reactants. NMR and electrospray ionization mass spectrometry analyses were employed to det. the synergistic nature of narcissistic self-sorting in this system, which depends on both the rigidity of the central core and the electronic donor ability of the aldehyde terminus. These expts. illustrate that significant control of self-sorting and self-assembly is possible upon extremely small variations in ligand structure, rigidity, and donor ability.
- 37Ronson, T. K.; Zarra, S.; Black, S. P.; Nitschke, J. R. Metal–organic Container Molecules through Subcomponent Self-Assembly. Chem. Commun. 2013, 49, 2476– 2490, DOI: 10.1039/c2cc36363a[Crossref], [PubMed], [CAS], Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlyjt7o%253D&md5=5ec9fdb77f4f246615a5e3c77b7e7b4bMetal-organic container molecules through subcomponent self-assemblyRonson, Tanya K.; Zarra, Salvatore; Black, Samuel P.; Nitschke, Jonathan R.Chemical Communications (Cambridge, United Kingdom) (2013), 49 (25), 2476-2490CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A review. A variety of different three-dimensional metal-org. container mols. have recently been prepd. using subcomponent self-assembly, which relies upon metal template effects to generate complex structures from simple mol. precursors and metal salts. Many of these structures have well defined internal pockets, allowing guest species to be bound and the chem. reactivity of these guests to be modified. Such host mols. have potential applications ranging from the protection of sensitive chem. species to the sepn. and purifn. of substrates as diverse as gases, gold compds., and fullerenes.
- 38Mosquera, J.; Ronson, T. K.; Nitschke, J. Subcomponent Flexibility Enables Conversion between D4-Symmetric CdII8L8 and T-Symmetric CdII4L4 Assemblies. J. Am. Chem. Soc. 2016, 138, 1812– 1815, DOI: 10.1021/jacs.5b12955[ACS Full Text], [CAS], Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVGktbs%253D&md5=9f3adadd61dab3a2c13122aadca955f2Subcomponent Flexibility Enables Conversion between D4-Symmetric CdII8L8 and T-Symmetric CdII4L4 AssembliesMosquera, Jesus; Ronson, Tanya K.; Nitschke, Jonathan R.Journal of the American Chemical Society (2016), 138 (6), 1812-1815CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A flexible tris-formylpyridine subcomponent A (I) was obsd. to produce three distinct products following CdII-templated self-assembly with different anilines. Two of the products were CdII4L4 tetrahedra (C192H172Cd4F48N32O46S16), one with ligands puckered inward, and the other outward. The third product was a CdII8L8 structure (C399H382.5Cd8F48N63.5O72S16) having all mer stereochem., contrasting with the fac stereochem. of the tetrahedra. These three complexes coexist in soln. The equil. between them could be influenced through guest binding and specific interactions between aniline subcomponents, allowing a selected one of the three to predominate under defined conditions.
- 39Fatila, E. M.; Twum, E. B.; Karty, J. A.; Flood, A. H. Ion Pairing and Co-Facial Stacking Drive High-Fidelity Bisulfate Assembly with Cyanostar Macrocyclic Hosts. Chem. - Eur. J. 2017, 23, 10652– 10662, DOI: 10.1002/chem.201701763[Crossref], [PubMed], [CAS], Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFOltrnK&md5=28a6c157e2472efedea70b7258fda2e1Ion Pairing and Co-facial Stacking Drive High-Fidelity Bisulfate Assembly with Cyanostar Macrocyclic HostsFatila, Elisabeth M.; Twum, Eric B.; Karty, Jonathan A.; Flood, Amar H.Chemistry - A European Journal (2017), 23 (44), 10652-10662CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Hydroxyanions pair up inside CH H-bonding cyanostar macrocycles, I, against Coulombic repulsions and solvation forces acting to sep. them. The driving forces responsible for assembly of bisulfate (HSO4-) dimers are unclear. We investigated them using solvent quality to tune the contributing forces and we take advantage of characteristic NMR signatures to follow the species distributions. We show that apolar solvents enhance ion pairing to stabilize formation of a 2:2:2 complex composed of π-stacked cyanostars encapsulating the [HSO4···HSO4]2- dimer and endcapped by tetrabutylammonium cations. Without cations engaged, a third macrocycle can be recruited with the aid of solvophobic forces in more polar solvents. The third macrocycle generates a more potent electropos. pocket in which to stabilize the anti-electrostatic anion dimer as a 3:2 assembly. We also see unprecedented evidence for a water mol. bound to the complex in the acetonitrile soln. In methanol, OH H-bonding leads to formation of 2:1 complexes by bisulfate solvation inside the macrocycles inhibiting anion dimers. Knowledge of the driving forces for stabilization (strong OH···O H-bonding, CH H-bonding, ion pairs, π-stacking) competing with destabilization (Coulomb repulsion, solvation) allows high-fidelity selection of the assemblies. Thermodn. stabilization of hydroxyanion dimers also demonstrates the ability to use macrocycles to control ion speciation and stoichiometry of the overall assemblies.
- 40Dobscha, J. R.; Debnath, S.; Fadler, R. E.; Fatila, E. M.; Pink, M.; Raghavachari, K.; Flood, A. H. Host-Host Interactions Control Self-Assembly and Switching of Triple and Double Decker Stacks of Tricarbazole Macrocycles Co-Assembled with Anti-Electrostatic Bisulfate Dimers. Chem. - Eur. J. 2018, 24, 9841– 9852, DOI: 10.1002/chem.201800827[Crossref], [PubMed], [CAS], Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtFGks7rJ&md5=9601acada1186918b4498c6391d9a09cHost-Host Interactions Control Self-assembly and Switching of Triple and Double Decker Stacks of Tricarbazole Macrocycles Co-assembled with anti-Electrostatic Bisulfate DimersDobscha, James R.; Debnath, Sibali; Fadler, Rachel E.; Fatila, Elisabeth M.; Pink, Maren; Raghavachari, Krishnan; Flood, Amar H.Chemistry - A European Journal (2018), 24 (39), 9841-9852CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Tricarbazole triazolophanes I [R = Me(CH2)n; n = 5, 8] were prepd.; I (n = 8) formed self-assembled 2:2 and 3:2 complexes with tetrabutylammonium bisulfate in 20% MeCN/CHCl3 and CHCl3, resp. In CHCl3, I formed high fidelity, triple-decker stacks with bisulfate dimers because of the greater strength of host-host interactions than of the ion-pairing interaction seen in more weakly-interacting oligomers. X-ray crystallog. of the 2:2:2 complex I·Bu4N+·HSO4- supported the idea that significant host-host interactions with I arise from dipole-stabilized π-stacking. Calcd. structures and free energies of solvation for model compds. further highlight the importance of host-host interactions in stacked complexes of I.
- 41
Substantial disorder of the oxygen atoms of the encapsulated HSO4– anions precluded accurate resolution of the hydrogen atom of these anions. However, the observed distance between the disordered HSO4– anions is consistent with the presence of a hydrogen-bonded dimer.
There is no corresponding record for this reference. - 42Bravin, C.; Guidetti, A.; Licini, G.; Zonta, C. Supramolecular Cages as Differential Sensors for Dicarboxylate Anions: Guest Length Sensing Using Principal Component Analysis of ESI-MS and 1H-NMR Raw Data. Chem. Sci. 2019, 10, 3523– 3528, DOI: 10.1039/C8SC05527K[Crossref], [PubMed], [CAS], Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXisFWlsb0%253D&md5=2489cdd6fa388eb9294bf85f481638eaSupramolecular cages as differential sensors for dicarboxylate anions: guest length sensing using principal component analysis of ESI-MS and 1H-NMR raw dataBravin, Carlo; Guidetti, Andrea; Licini, Giulia; Zonta, CristianoChemical Science (2019), 10 (12), 3523-3528CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Dynamic covalent libraries (DCLs) have been widely used in the development of differential sensors. Inspired by recent studies which use supramol. recognition systems for sensing, we report the use of a tris(-pyridylmethyl)amine (TPMA)-based supramol. cage as a differential sensor for dicarboxylate anions. In particular, a library of mol. cages constituted by linkers differing in size and flexibility was allowed to equilibrate toward a series of guests differing in mol. size. The differential system was able to discriminate a series of dicarboxylates depending on their chain length. This differentiation was evaluated through the application of the Principal Component Anal. (PCA) method using interpolated and raw data obtained from ESI-MS. Interestingly, while the 1H NMR spectra of the differential system did not allow for the discrimination of the analytes by the naked eye, PCA of the raw data from the spectra revealed information on the chain length of the guest and also on the odd-even character of the carbon chain.
- 43Clever, G. H.; Kawamura, W.; Shionoya, M. Encapsulation versus Aggregation of Metal–Organic Cages Controlled by Guest Size Variation. Inorg. Chem. 2011, 50, 4689– 4691, DOI: 10.1021/ic200517r[ACS Full Text], [CAS], Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXltFGmsbY%253D&md5=fe5c398c6930d0df1174cce751b71d0dEncapsulation versus Aggregation of Metal-Organic Cages Controlled by Guest Size VariationClever, Guido H.; Kawamura, Wataru; Shionoya, MitsuhikoInorganic Chemistry (2011), 50 (11), 4689-4691CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The strength and mode of binding (inside vs. outside) of arenedisulfonate bisanionic guest mols. to a cationic, self-assembled dinuclear palladium metal-org. cage depend on their size and the stoichiometry of the addn. Herein the compn. of the solid/liq. phase of a heterogeneous system can be kinetically controlled by the order of the addn. of two different guest compds.
- 44Minisci, F.; Citterio, A.; Giordano, C. Electron-Transfer Processes: Peroxydisulfate, a Useful and Versatile Reagent in Organic Chemistry. Acc. Chem. Res. 1983, 16, 27– 32, DOI: 10.1021/ar00085a005[ACS Full Text], [CAS], Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXlt1OhtA%253D%253D&md5=fa910a18ba21cc9a983724c3c61940dfElectron-transfer processes: peroxydisulfate, a useful and versatile reagent in organic chemistryMinisci, Francesco; Citterio, Attilio; Giordano, ClaudioAccounts of Chemical Research (1983), 16 (1), 27-32CODEN: ACHRE4; ISSN:0001-4842.A review with >40 refs.
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- Lauren K. Macreadie, Alexander M. Gilchrist, Daniel A. McNaughton, William G. Ryder, Mohamed Fares, Philip A. Gale. Progress in anion receptor chemistry. Chem 2022, 8 (1) , 46-118. https://doi.org/10.1016/j.chempr.2021.10.029
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Abstract
Figure 1
Figure 1. (a) Synthesis of AgI12L6 trigonal prism 1 from tris(4-aminophenyl)amine A, 2-formyl-1,8-naphthyridine B, and silver(I) perchlorate. (b) Assembly of 1 requires an appropriate template anion. (c) X-ray crystal structure of (ClO4–)2⊂1 with the two templating anions included. One pair of ligands is shown in gray to highlight the desymmetrization of the ligand arms. (d) Top-down view depicting the central tubular void of (ClO4–)2⊂1. Disorder, nonincluded anions, and solvent molecules have been omitted for clarity.
Figure 2
Figure 2. (a) One vertex of (ClO4–)2⊂1. (b) Simplified representation of the same vertex. (c) 1H NMR and DOSY NMR spectra (400 MHz, 298 K, CD3CN) of (ClO4–)2⊂1 showing 3-fold desymmetrization of the cage ligands. The units of D are 10–6 cm2 s–1.
Figure 3
Figure 3. X-ray crystal structures of (a) (HSO4–)2⊂1, (b) (ClO4–)2⊂1, (c) (PF6–)2⊂1, (d) (EDS2–)⊂1 and (e) (S2O82–)⊂1 with side-views of the isolated anionic templates.
References
ARTICLE SECTIONSThis article references 44 other publications.
- 1Chand, D. K.; Biradha, K.; Fujita, M.; Sakamoto, S.; Yamaguchi, K. A Molecular Sphere of Octahedral Symmetry. Chem. Commun. 2002, 2486– 2487, DOI: 10.1039/B206625B[Crossref], [CAS], Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotVymu7s%253D&md5=678dce946bca79cbc3180efd41a8e1aaA molecular sphere of octahedral symmetryChand, Dillip Kumar; Biradha, Kumar; Fujita, Makoto; Sakamoto, Shigeru; Yamaguchi, KentaroChemical Communications (Cambridge, United Kingdom) (2002), (21), 2486-2487CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Complexation of tridentate ligand 1,3,5-tris(4-pyridylmethyl)benzene (L) with Pd(NO3)2 leads to the quant. self-assembly of M6L8 mol. sphere (1). 1 Is tetragonal, space group P41/nmm, Z = 4, R1 = 0.1203, wR2 = 0.2800. The av. distance between axially located Pd centers in the giant, hollow sphere of 1 is 15.2 Å.
- 2Freye, S.; Michel, R.; Stalke, D.; Pawliczek, M.; Frauendorf, H.; Clever, G. H. Template Control over Dimerization and Guest Selectivity of Interpenetrated Coordination Cages. J. Am. Chem. Soc. 2013, 135, 8476– 8479, DOI: 10.1021/ja403184a[ACS Full Text], [CAS], Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXotV2rt7s%253D&md5=7194ccd01d5ec010a14968aa2ff18dd7Template Control over Dimerization and Guest Selectivity of Interpenetrated Coordination CagesFreye, Sabrina; Michel, Reent; Stalke, Dietmar; Pawliczek, Martin; Frauendorf, Holm; Clever, Guido H.Journal of the American Chemical Society (2013), 135 (23), 8476-8479CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors have previously shown that the self-assembly of dibenzosuberone-based bis-monodentate pyridyl ligands L1 with PdII cations leads to the quant. formation of interpenetrated coordination cages [[email protected]]. The BF4- anion inside the central cavity serves as a template, causing the outer two pockets to show a tremendous affinity for allosteric binding of two small chloride anions. Derivatization of the ligand backbone with a bulky aryl substituent allows the authors to control the dimerization and hence the guest-binding ability of the cage by the choice of the templating anion. Steric constraints imposed by L2 (L2 is L1 deriv. by adding substituted phenyl) prevent the large BF4- anion from serving as a template for the formation of interpenetrated double cages. Instead, a single isomer of the monomeric cage [Pd2L24] is formed. Addn. of the small anionic template Cl- permits dimerization, yielding the interpenetrated double cage [[email protected]], whose enlarged outer pockets show a preference for the binding of large anions such as ReO4-.
- 3Yazaki, K.; Sei, Y.; Akita, M.; Yoshizawa, M. A Polyaromatic Molecular Tube That Binds Long Hydrocarbons with High Selectivity. Nat. Commun. 2014, 5, 5179, DOI: 10.1038/ncomms6179[Crossref], [PubMed], [CAS], Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVeks70%253D&md5=d6fc892bd2d729096dda6e504ececfadA polyaromatic molecular tube that binds long hydrocarbons with high selectivityYazaki, Kohei; Sei, Yoshihisa; Akita, Munetaka; Yoshizawa, MichitoNature Communications (2014), 5 (), 5179CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)Long hydrocarbon chains are essential components of biomols. used for structure and function in living organisms. The selective recognition and effective binding of hydrocarbons within synthetic host compds. are problematic owing to their conformational flexibility and the lack of specific binding sites. Here we report a mol. tube with polyarom. frameworks prepd. by the Zincke cross-coupling reaction. The tube has a well-defined cylindrical cavity with a diam. and length of ∼1 nm encircled by multiple anthracene panels and thereby binds long hydrocarbons contg. branched Me groups and/or unsatd. carbon-carbon double bonds (for example, heptamethylnonane, nervonic acid ester and squalene) with high selectivity in aq. solns.
- 4Argent, S. P.; Adams, H.; Riis-Johannessen, T.; Jeffery, J. C.; Harding, L. P.; Ward, M. D. High-Nuclearity Homoleptic and Heteroleptic Coordination Cages Based on Tetra-Capped Truncated Tetrahedral and Cuboctahedral Metal Frameworks. J. Am. Chem. Soc. 2006, 128, 72– 73, DOI: 10.1021/ja056993o[ACS Full Text], [CAS], Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1ynsr7J&md5=18aa2207c21aa69f2ae9357882a6a73eHigh-nuclearity Homoleptic and Heteroleptic Coordination Cages Based on Tetra-Capped Truncated Tetrahedral and Cuboctahedral Metal FrameworksArgent, Stephen P.; Adams, Harry; Riis-Johannessen, Thomas; Jeffery, John C.; Harding, Lindsay P.; Ward, Michael D.Journal of the American Chemical Society (2006), 128 (1), 72-73CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two new types of coordination cage were prepd. and structurally characterized: [M16(μ-L1)24]X32 (M = Zn, Cd; X = BF4, ClO4; L1 = 1,4-bis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) are based on a tetra-capped truncated tetrahedral core and have a bridging ligand L1 along each of the 24 edges; [M12(μ-L1)12(μ3-L2)4]X24 (M = Cu, Co, Cd; L2 = 1,3,5-trimethyl-2,4,6-tris(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) are based on a cuboctahedral core which is supported by a combination of face-capping ligands L2 and edge-bridging ligands L1. The crystal structures of 2 of these complexes were detd. The difference between the two illustrates how combinations of ligands with different coordination modes can generate coordination cages which are not available using one ligand type on its own.
- 5Riddell, I. A.; Hristova, Y. R.; Clegg, J. K.; Wood, C. S.; Breiner, B.; Nitschke, J. R. Five Discrete Multinuclear Metal-Organic Assemblies from One Ligand: Deciphering the Effects of Different Templates. J. Am. Chem. Soc. 2013, 135, 2723– 2733, DOI: 10.1021/ja311285b[ACS Full Text], [CAS], Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlemuro%253D&md5=3af02bf70846b96be800f60b8e9db4dbFive Discrete Multinuclear Metal-Organic Assemblies from One Ligand: Deciphering the Effects of Different TemplatesRiddell, Imogen A.; Hristova, Yana R.; Clegg, Jack K.; Wood, Christopher S.; Breiner, Boris; Nitschke, Jonathan R.Journal of the American Chemical Society (2013), 135 (7), 2723-2733CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A rigid org. ligand, formed through the subcomponent self-assembly of p-toluidine and 6,6'-diformyl-3,3'-bipyridine, was employed in a systematic investigation into the synergistic and competing effects of metal and anion templation. A range of discrete and polymeric metal-org. complexes were formed, many of which represent structure types that have not previously been obsd. and whose formation would not be predicted on taking into account solely geometric considerations. These complex structures, capable of binding multiple guests within individual binding pockets, were characterized by NMR, ESI-MS, and single-crystal x-ray diffraction. The factors that stabilize individual complexes and give one over another are discussed.
- 6Jansze, S. M.; Wise, M. D.; Vologzhanina, A. V.; Scopelliti, R.; Severin, K. PdII2L4-Type Coordination Cages up to Three Nanometers in Size. Chem. Sci. 2017, 8, 1901– 1908, DOI: 10.1039/C6SC04732G[Crossref], [PubMed], [CAS], Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjsVyqsbo%253D&md5=de8545e2ece956ec7cd9addef19a1b6fPdII2L4-type coordination cages up to three nanometers in sizeJansze, Suzanne M.; Wise, Matthew D.; Vologzhanina, Anna V.; Scopelliti, Rosario; Severin, KayChemical Science (2017), 8 (3), 1901-1908CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The use of large ligands in coordination-based self-assembly represents an attractive strategy for the construction of supramol. assemblies more than two nanometers in size. However, the implementation of this strategy is hampered by the fact that the prepn. of such ligands often requires substantial synthetic effort. Herein, the authors describe a simple one-step protocol, which allows large bipyridyl ligands with a bent shape to be synthesized from easily accessible and/or com. available starting materials. The ligands were used to construct PdII2L4-type coordination cages of unprecedented size. Furthermore, the authors provide evidence that these cages may be stabilized by close intramol. packing of lipophilic ligand side chains. Packing effects of this kind are frequently encountered in protein assemblies, but they are seldom used as a design element in metallasupramol. chem.
- 7Sun, Q.-F.; Sato, S.; Fujita, M. An M18L24 Stellated Cuboctahedron through Post-Stellation of an M12L24 Core. Nat. Chem. 2012, 4, 330– 333, DOI: 10.1038/nchem.1285[Crossref], [PubMed], [CAS], Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1Whsb4%253D&md5=72a946106b40e8458bc08543404539f9An M18L24 stellated cuboctahedron through post-stellation of an M12L24 coreSun, Qing-Fu; Sato, Sota; Fujita, MakotoNature Chemistry (2012), 4 (4), 330-333CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)Platonic and Archimedean polyhedra, known to mathematicians, were recently constructed by chemists at a mol. scale by defining the vertexes and the edges with metal ions (M) and org. ligands (L), resp. Here, the authors report the 1st synthesis of a concave-surface 'stellated polyhedron', constructed by extending the faces of its precursor polyhedron until they intersect, forming addnl. nodes. The authors' approach involves the formation of an M12L24 cuboctahedron core, the linkers of which each bear a pendant ligand site that is subsequently able to bind an addnl. metal center to form the stellated M18L24 cuboctahedron. The [Pd12L124](BF4)24, [Pd12L124](PF6)24, [Pd18L124](BF4)36, [Pd18L224](CF3SO3)36 and [Pd18L224](NO3)36 complexes (L1 = 1,3-bis(pyridin-4-yl)-5-(pyridin-4-yloxymethyl)benzene, L2 = pyridin-4-ylmethyl 1,3-bis(pyridin-4-yl)benzoate) were prepd., and [Pd12L124](PF6)24 and [Pd18L224](CF3SO3)36 were characterized by x-ray crystallog. During this post-stellation process, the square faces of the M12L24 core are closed by coordination of the pendant moieties to the addnl. metal centers, but they are reopened on removing these metals ions from the vertexes. This behavior is reminiscent of the analogous metal-triggered gate opening-closing switches found in spherical virus capsids.
- 8Suzuki, K.; Sato, S.; Fujita, M. Template Synthesis of Precisely Monodisperse Silica Nanoparticles within Self-Assembled Organometallic Spheres. Nat. Chem. 2010, 2, 25– 29, DOI: 10.1038/nchem.446[Crossref], [PubMed], [CAS], Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFKns73O&md5=1ee470ffea0ef1e84d0dbddd295ccc5eTemplate synthesis of precisely monodisperse silica nanoparticles within self-assembled organometallic spheresSuzuki, Kosuke; Sato, Sota; Fujita, MakotoNature Chemistry (2010), 2 (1), 25-29CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)One of the key challenges in materials science is to control the size and shape of inorg. nanoparticles with a high degree of precision, as these parameters have a significant influence on the nanoparticles' properties and potential applications. Here, the authors describe the prepn. of highly monodisperse nanoparticles smaller than 5 nm in diam. by using self-assembled, hollow, spherical compds. as endo-templates'. These coordination complexes with pendant sugar groups lining their interiors-assembled from 12 metal ions and 24 bis-pyridyl ligands contg. substituents-acted as structurally well-defined templates for the sol-gel condensation of alkoxysilanes. The polydispersities of the nanoparticles made with this method approached unity, with Mw/Mn < 1.01. The component ligands are modified easily, which enables an accurate expansion of the coordination complex and the subsequent control of the monodisperse nanoparticles that span mol. wts. of 5,000 to 31,000 Da (corresponding to 2-4 nm in diam.). This method could be applicable to the prepn. of other inorg. nanoparticles.
- 9Yu, F.; Poole, D.; Mathew, S.; Yan, N.; Hessels, J.; Orth, N.; Ivanović-Burmazović, I.; Reek, J. N. H. Control over Electrochemical Water Oxidation Catalysis by Preorganization of Molecular Ruthenium Catalysts in Self-Assembled Nanospheres. Angew. Chem., Int. Ed. 2018, 57, 11247– 11251, DOI: 10.1002/anie.201805244[Crossref], [CAS], Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVWhurrE&md5=16242cf076c22371bbb95bbf2f826d7cControl over Electrochemical Water Oxidation Catalysis by Preorganization of Molecular Ruthenium Catalysts in Self-Assembled NanospheresYu, Fengshou; Poole, David III; Mathew, Simon; Yan, Ning; Hessels, Joeri; Orth, Nicole; Ivanovic-Burmazovic, Ivana; Reek, Joost N. H.Angewandte Chemie, International Edition (2018), 57 (35), 11247-11251CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Oxygen formation through water oxidn. catalysis is a key reaction in the context of fuel generation from renewable energies. The no. of homogeneous catalysts that catalyze water oxidn. at high rate with low overpotential is limited. Ruthenium complexes can be particularly active, esp. if they facilitate a dinuclear pathway for oxygen bond formation step. A supramol. encapsulation strategy is reported that involves preorganization of dil. solns. (10-5 M) of ruthenium complexes to yield high local catalyst concns. (up to 0.54 M). The preorganization strategy enhances the water oxidn. rate by two-orders of magnitude to 125 s-1, as it facilitates the diffusion-controlled rate-limiting dinuclear coupling step. Moreover, it modulates reaction rates, enabling comprehensive elucidation of electrocatalytic reaction mechanisms.
- 10Zhang, D.; Ronson, T. K.; Mosquera, J.; Martinez, A.; Guy, L.; Nitschke, J. R. Anion Binding in Water Drives Structural Adaptation in an Azaphosphatrane-Functionalized FeII4L4 Tetrahedron. J. Am. Chem. Soc. 2017, 139, 6574– 6577, DOI: 10.1021/jacs.7b02950[ACS Full Text], [CAS], Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntVGgsrc%253D&md5=b8bc86bec757f149e36de5c63e0bd457Anion Binding in Water Drives Structural Adaptation in an Azaphosphatrane-Functionalized FeII4L4 TetrahedronZhang, Dawei; Ronson, Tanya K.; Mosquera, Jesus; Martinez, Alexandre; Guy, Laure; Nitschke, Jonathan R.Journal of the American Chemical Society (2017), 139 (19), 6574-6577CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Anion-templated aq. self-assembly resulted in the formation of an endohedrally functionalized FeII4L4 tetrahedron from azaphosphatrane-based subcomponents. This new water-sol. cage is flexible and able to encapsulate anions with vols. ranging from 35 to 219 Å3 via hydrogen bonding and electrostatic interactions. It structurally adapts in response to the size and shape of the template anions, dynamically adopting a conformation either where all four azaphosphatrane +P-H vectors point inward, or else where one points outward and the other three inward. The two cage isomers can coexist in soln. and interconvert. A shape memory phenomenon was obsd. during guest displacement because guest exchange occurs more rapidly than structural reconfiguration.
- 11Custelcean, R.; Bonnesen, P. V.; Duncan, N. C.; Zhang, X.; Watson, L. A.; Van Berkel, G.; Parson, W. B.; Hay, B. P. Urea-Functionalised M4L6 Cage Receptors: Anion-Templated Self-Assembly and Selective Guest Exchange in Aqueous Solutions. J. Am. Chem. Soc. 2012, 134, 8525– 8534, DOI: 10.1021/ja300677w[ACS Full Text], [CAS], Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xmt1OqtLs%253D&md5=6339ecb163512efd336a38b60130615aUrea-Functionalized M4L6 Cage Receptors: Anion-Templated Self-Assembly and Selective Guest Exchange in Aqueous SolutionsCustelcean, Radu; Bonnesen, Peter V.; Duncan, Nathan C.; Zhang, Xiaohua; Watson, Lori A.; Van Berkel, Gary; Parson, Whitney B.; Hay, Benjamin P.Journal of the American Chemical Society (2012), 134 (20), 8525-8534CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors present an extensive study of a novel class of de novo designed tetrahedral M4L6 (M = Ni, Zn) cage receptors, wherein internal decoration of the cage cavities with urea anion-binding groups, via functionalization of the org. components L, led to selective encapsulation of tetrahedral oxoanions EO4n- (E = S, Se, Cr, Mo, W, n = 2; E = P, n = 3) from aq. solns., based on shape, size, and charge recognition. External functionalization with tBu groups led to enhanced soly. of the cages in aq. MeOH solns., thereby allowing for their thorough characterization by multinuclear (1H, 13C, 77Se) and diffusion NMR spectroscopies. Addnl. exptl. characterization by electrospray ionization mass spectrometry, UV-visible spectroscopy, and single-crystal x-ray diffraction, as well as theor. calcns., led to a detailed understanding of the cage structures, self-assembly, and anion encapsulation. The cage self-assembly is templated by EO4n- oxoanions (n ≥ 2), and upon removal of the templating anion the tetrahedral M4L6 cages rearrange into different coordination assemblies. The exchange selectivity among EO4n- oxoanions was studied with 77Se NMR spectroscopy using 77SeO42- as an anionic probe, which found the following selectivity trend: PO43- » CrO42- > SO42- > SeO42- > MoO42- > WO42-. In addn. to the complementarity and flexibility of the cage receptor, a combination of factors contribute to the obsd. anion selectivity, including the anions' charge, size, hydration, basicity, and H-bond acceptor abilities.
- 12Custelcean, R.; Bonnesen, P. V.; Roach, B. D.; Duncan, N. C. Ion-pair triple helicates and mesocates self-assembled from ditopic 2,2’-bipyridine-bis(urea) ligands and Ni(II) or Fe(II) sulfate salts. Chem. Commun. 2012, 48, 7438– 7440, DOI: 10.1039/c2cc33062h[Crossref], [PubMed], [CAS], Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XpsVOiuro%253D&md5=c2c79638bc33d7c1c02aa093a8edd60cIon-pair triple helicates and mesocates self-assembled from ditopic 2,2'-bipyridinebis(urea) ligands and Ni(II) or Fe(II) sulfate saltsCustelcean, Radu; Bonnesen, Peter V.; Roach, Benjamin D.; Duncan, Nathan C.Chemical Communications (Cambridge, United Kingdom) (2012), 48 (60), 7438-7440CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)NiSO4 and FeSO4 self-assemble with heteroditopic ligands (L) comprising 2,2'-bipyridine and o-phenylene-(bis)urea cation- and anion-binding sites, resp., into [ML3SO4] (M = Ni2+, Fe2+) triple-stranded ion-pair helicates and mesocates.
- 13Albrecht, M.; Isaak, E.; Baumert, M.; Gossen, V.; Raabe, G.; Fröhlich, R. Induced Fit” in Chiral Recognition: Epimerization upon Dimerization in the Hierarchical Self-Assembly of Helicate-Type Titanium(IV) Complexes. Angew. Chem., Int. Ed. 2011, 50, 2850– 2853, DOI: 10.1002/anie.201006448[Crossref], [CAS], Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXivVGhtrk%253D&md5=def95b0714e2842e4ebacf57fa09a550"Induced Fit" in Chiral Recognition: Epimerization upon Dimerization in the Hierarchical Self-Assembly of Helicate-type Titanium(IV) ComplexesAlbrecht, Markus; Isaak, Elisabeth; Baumert, Miriam; Gossen, Verena; Raabe, Gerhard; Froehlich, RolandAngewandte Chemie, International Edition (2011), 50 (12), 2850-2853, S2850/1-S2850/7CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Chiral esters (H2L) were prepd. from the reaction of 2,3-dihydroxybenzoic acid with (S)-citronellol and (S)-phenylethanol and form titanium tris(catecholates) Li2[TiL3] and Li[Li3{TiL3}2] which are characterized by CD spectra and in one case K[Li3{TiL3}2] by crystal structure anal. These complexes present a unique example of stereoinduction, in which the stereochem. at a labile metal complex unit is inverted and locked upon Li mediated dimerization. The stereocontrol can be explained by different conformations at the ester in the monomer and the dimer and is impressive in the context of dynamic chiral resoln. in a supramol. system following induced fit based on stereorecognition.
- 14Mal, P.; Breiner, B.; Rissanen, K.; Nitschke, J. R. White Phosphorus Is Air-Stable within a Self-Assembled Tetrahedral Capsule. Science 2009, 324, 1697– 1699, DOI: 10.1126/science.1175313[Crossref], [PubMed], [CAS], Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnsFOmsb0%253D&md5=bba55618442f24b69b6c10f462acab60White Phosphorus Is Air-Stable Within a Self-Assembled Tetrahedral CapsuleMal, Prasenjit; Breiner, Boris; Rissanen, Kari; Nitschke, Jonathan R.Science (Washington, DC, United States) (2009), 324 (5935), 1697-1699CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The air-sensitive nature of white phosphorus underlies its destructive effect as a munition; tetrahedral P4 mols. readily react with atm. dioxygen, leading this form of the element to spontaneously combust upon exposure to air. Here, hydrophobic P4 mols. are rendered air-stable and water-sol. within the hydrophobic hollows of self-assembled tetrahedral container mols., [Fe4L6]4- (L = 4,4'-bis(2-pyridylmethyleneamino)-1,1'-biphenyl-2,2'-disulfonate), which form in water from simple org. subcomponents and iron(II) ions. The host-guest complex with P4 was characterized by x-ray crystallog. This stabilization is not achieved through hermetic exclusion of O2 but rather by constriction of individual P4 mols.; the addn. of oxygen atoms to P4 would gave oxidized species too large for their containers. The phosphorus can be released in controlled fashion without disrupting the cage by adding the competing guest benzene.
- 15Cullen, W.; Misuraca, M. C.; Hunter, C. A.; Williams, N. H.; Ward, M. D. Highly Efficient Catalysis of the Kemp Elimination in the Cavity of a Cubic Coordination Cage. Nat. Chem. 2016, 8, 231– 236, DOI: 10.1038/nchem.2452[Crossref], [PubMed], [CAS], Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XislOlt74%253D&md5=4d3995ec0e5fd4bb58b826b6d9b5754dHighly efficient catalysis of the Kemp elimination in the cavity of a cubic coordination cageCullen, William; Misuraca, M. Cristina; Hunter, Christopher A.; Williams, Nicholas H.; Ward, Michael D.Nature Chemistry (2016), 8 (3), 231-236CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)The hollow cavities of coordination cages can provide an environment for enzyme-like catalytic reactions of small-mol. guests. Here, we report a new example (catalysis of the Kemp elimination reaction of benzisoxazole with hydroxide to form 2-cyanophenolate) in the cavity of a water-sol. M8L12 coordination cage, with two features of particular interest. First, the rate enhancement is among the largest obsd. to date: at pD 8.5, the value of kcat/kuncat is 2 × 105, due to the accumulation of a high concn. of partially desolvated hydroxide ions around the bound guest arising from ion-pairing with the 16+ cage. Second, the catalysis is based on two orthogonal interactions: (1) hydrophobic binding of benzisoxazole in the cavity and (2) polar binding of hydroxide ions to sites on the cage surface, both of which were established by competition expts.
- 16Murase, T.; Nishijima, Y.; Fujita, M. Cage-Catalyzed Knoevenagel Condensation under Neutral Conditions in Water. J. Am. Chem. Soc. 2012, 134, 162– 164, DOI: 10.1021/ja210068f[ACS Full Text], [CAS], Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFyltbbP&md5=0f5a9c3aff795de3709a9d5f580cb65fCage-Catalyzed Knoevenagel Condensation under Neutral Conditions in WaterMurase, Takashi; Nishijima, Yuki; Fujita, MakotoJournal of the American Chemical Society (2012), 134 (1), 162-164CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A cationic coordination cage dramatically accelerates the Knoevenagel condensation of arom. aldehydes in water under neutral conditions. The addn. of a nucleophile to the aldehyde to generate anionic intermediates seems to be facilitated by the cationic environment of the cavity. The products, e.g. I, are ejected from the cage as a result of the host-guest size discrepancy. As a result, the condensation is promoted by a catalytic amt. of the cage.
- 17Rizzuto, F. J.; Pröhm, P.; Plajer, A. J.; Greenfield, J. L.; Nitschke, J. R. Hydrogen-Bond-Assisted Symmetry Breaking in a Network of Chiral Metal–Organic Assemblies. J. Am. Chem. Soc. 2019, 141, 1707– 1715, DOI: 10.1021/jacs.8b12323[ACS Full Text], [CAS], Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkslOrtg%253D%253D&md5=24a60b5dfdfb0c3299ddf6aff861a4d4Hydrogen-Bond-Assisted Symmetry Breaking in a Network of Chiral Metal-Organic AssembliesRizzuto, Felix J.; Prohm, Patrick; Plajer, Alex J.; Greenfield, Jake L.; Nitschke, Jonathan R.Journal of the American Chemical Society (2019), 141 (4), 1707-1715CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Herein the authors elucidate the interplay of chiral, chelate, solvent, and hydrogen-bonding information in the self-assembly of a series of new three-dimensional metal-org. architectures. Enantiopure ligands, each contg. H-bond donors and acceptors, form different structures, depending on the ratio in which they are combined: enantiopure components form M4L4 assemblies, whereas racemic mixts. form M3L3 stacks. Chiral amplification within M3L3 enantiomers was obsd. when a 2:1 ratio of R and S subcomponent enantiomers was employed. Simply switching the solvent (from MeCN to MeOH) or chelating unit (from bidentate to tridentate) increased the diversity of structures that can be generated from these building blocks, leading to the selective formation of novel M2L2 and M3L2 assemblies. The addn. of achiral ligand building blocks gave further structures: When an achiral subcomponent was combined with its R and S chiral congeners, a three-layer heteroleptic architecture was generated, with the achiral unit sitting at the top of the stack. When combined with the S enantiomer only, however, the achiral unit assembled in the center of the structure, thus demonstrating the selective placement of achiral units within chiral systems. Further sorting expts. revealed that combining R and S stereocenters within a single ligand led to diastereoselective product generation. These results show how geometric complementarity between different ligands impacts upon the degree of hydrogen-bonding within the assembly, stabilizing specific low-symmetry architectures from among many possible structural outcomes.
- 18Song, B.; Kandapal, S.; Gu, J.; Zhang, K.; Reese, A.; Ying, Y.; Wang, L.; Wang, H.; Li, Y.; Wang, M.; Lu, S.; Hao, X.-Q.; Li, X.; Xu, B.; Li, X. Self-Assembly of Polycyclic Supramolecules Using Linear Metal-Organic Ligands. Nat. Commun. 2018, 9, 4575, DOI: 10.1038/s41467-018-07045-9[Crossref], [PubMed], [CAS], Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3cvlslKkug%253D%253D&md5=f0139e943db88ab2c277b93f1c270d87Self-assembly of polycyclic supramolecules using linear metal-organic ligandsSong Bo; Wang Lei; Wang Heng; Li Yiming; Li Xiaopeng; Kandapal Sneha; Zhang Keren; Reese Alex; Xu Bingqian; Gu Jiali; Li Xiaohong; Ying Yuanfang; Wang Ming; Lu Shuai; Hao Xin-QiNature communications (2018), 9 (1), 4575 ISSN:.Coordination-driven self-assembly as a bottom-up approach has witnessed a rapid growth in building giant structures in the past few decades. Challenges still remain, however, within the construction of giant architectures in terms of high efficiency and complexity from simple building blocks. Inspired by the features of DNA and protein, which both have specific sequences, we herein design a series of linear building blocks with specific sequences through the coordination between terpyridine ligands and Ru(II). Different generations of polycyclic supramolecules (C1 to C5) with increasing complexity are obtained through the self-assembly with Cd(II), Fe(II) or Zn(II). The assembled structures are characterized via multi-dimensional mass spectrometry analysis as well as multi-dimensional and multinuclear NMR ((1)H, COSY, NOESY) analysis. Moreover, the largest two cycles C4 and C5 hierarchically assemble into ordered nanoscale structures on a graphite based on their precisely-controlled shapes and sizes with high shape-persistence.
- 19Hasenknopf, B.; Lehn, J.-M.; Boumediene, N.; Dupont-Gervais, A.; Van Dorsselaer, A.; Kneisel, B.; Fenske, D. Self-Assembly of Tetra- and Hexanuclear Circular Helicates. J. Am. Chem. Soc. 1997, 119, 10956– 10962, DOI: 10.1021/ja971204r[ACS Full Text], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXnt1Ohur0%253D&md5=c9ac3a9917463f3cbe31ebe5adfa1488Self-Assembly of Tetra- and Hexanuclear Circular HelicatesHasenknopf, Bernold; Lehn, Jean-Marie; Boumediene, Nedjia; Dupont-Gervais, Annick; Van Dorsselaer, Alain; Kneisel, Boris; Fenske, DieterJournal of the American Chemical Society (1997), 119 (45), 10956-10962CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The self-assembly of the tris-bipyridine ligands BI (5,5'-bis[2-(5'-methyl-2,2'-bipyridin-5-yl)ethyl]2,2'-bipyridine) and BII (5,5'-bis[(5'-methyl-2,2'-bipyridin-5-yl)methoxymethyl]2,2'-bipyridine) with iron(II) salts yields polynuclear complexes displaying structures of cyclic double-helix type, termed circular helicates [n]cH (of order n). With BI, in which the bipyridine units in the ligand are connected by ethylene bridges, penta- or hexanuclear architectures [5]cH ([Fe5BI5]10+) and [6]cH ([Fe6BI6]12+) were obtained, depending on the anion present during the self-assembly process. The elongated tris-bipyridine ligand BII with oxypropylene bridges forms a tetranuclear circular helicate [4]cH ([Fe4BII4](PF6)8), whose structure was confirmed by crystal structure detn. as a solvate (tetragonal, space group P4/n, R1 = 0.1178). The possible oligomeric combinations of tris-bipy ligands and iron(II) ions may be considered to constitute the potential members of a virtual combinatorial library, generated via dynamic combinatorial chem., from which a specific real constituent of the virtual set of circular helicates is expressed in given conditions.
- 20Hasenknopf, B.; Lehn, J.-M.; Kneisel, B. O.; Baum, G.; Fenske, D. Self-Assembly of a Circular Double Helicate. Angew. Chem., Int. Ed. 1996, 35, 1838– 1840, DOI: 10.1002/anie.199618381[Crossref], [CAS], Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xls1Gqtbo%253D&md5=5a9015849f62c0b55a27db4d6c724bb3Self-assembly of a circular double helicateHasenknopf, Bernold; Lehn, Jean-Marie; Kneisel, Boris O.; Baum, Gerhard; Fenske, DieterAngewandte Chemie, International Edition in English (1996), 35 (16), 1838-1840CODEN: ACIEAY; ISSN:0570-0833. (VCH)Reaction of tris(bipyridyl) ligand I (L) with 1 equiv FeCl2 in ethylene glycol at 170°, followed by addn. of NH4PF6, afforded a red solid analyzed as [(Fe5L5)Cl](PF6)9 (1H NMR, ESI-MS, IR, UV-visible spectra). The crystal structure of [{(Fe5L5)Cl}2](PF6)17.5Cl0.5·11MeNO2·40.5H2O was detd. by x-ray crystallog. (monoclinic, space group P2/n). The [Fe5L5]10+ cation may be described as a circular double helix resulting in a torus which is a specific receptor of chloride ion, as evidenced by its strong binding to Cl-. The salt of the chiral cation is obtained as a racemic mixt.; full resoln. of the two enantiomers was not achieved. The [Fe5L5Cl]9+ cation is presented as a combinatorial generation of a receptor by self-assembly of a set of components into an entity that most strongly binds the substrate. In other words, the cations pentameric cyclic structure is selected among all possible oligomers when chloride ions are present; other entities may be formed with other anions.
- 21Hasenknopf, B.; Lehn, J.-M.; Boumediene, N.; Leize, E.; Van Dorsselaer, A. Kinetic and Thermodynamic Control in Self-Assembly: Sequential Formation of Linear and Circular Helicates. Angew. Chem., Int. Ed. 1998, 37, 3265– 3268, DOI: 10.1002/(SICI)1521-3773(19981217)37:23<3265::AID-ANIE3265>3.0.CO;2-B[Crossref], [CAS], Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksVejsw%253D%253D&md5=f44150612b7820b40fcd51c0181dc62eKinetic and thermodynamic control in self-assembly: sequential formation of linear and circular helicatesHasenknopf, Bernold; Lehn, Jean-Marie; Boumediene, Nedjia; Leize, Emmanuelle; Van Dorsselaer, AlainAngewandte Chemie, International Edition (1998), 37 (23), 3265-3268CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The self-assembly process for the formation of linear and circular helicates was studied in order to det. the structural, mechanistic and physicochem. factors affecting the formation process. The reaction of the tris(bipyridine) ligand L (L = I) with FeCl2 or NiCl2 is shown to first form a linear triple helicate complex [M3L3]6- (M = Fe, Ni) which upon continued heating transforms to a circular helicate complex [M5L5]9-. The linear helicate structure the kinetically favored product.
- 22Cullen, W.; Metherell, A. J.; Wragg, A. B.; Taylor, C. G. P.; Williams, N. H.; Ward, M. D. Catalysis in a Cationic Coordination Cage Using a Cavity-Bound Guest and Surface-Bound Anions: Inhibition, Activation, and Autocatalysis. J. Am. Chem. Soc. 2018, 140, 2821– 2828, DOI: 10.1021/jacs.7b11334[ACS Full Text], [CAS], Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitl2mur0%253D&md5=6688f27c05075b2cf9bea7b548692a47Catalysis in a Cationic Coordination Cage Using a Cavity-Bound Guest and Surface-Bound Anions: Inhibition, Activation, and AutocatalysisCullen, William; Metherell, Alexander J.; Wragg, Ashley B.; Taylor, Christopher G. P.; Williams, Nicholas H.; Ward, Michael D.Journal of the American Chemical Society (2018), 140 (8), 2821-2828CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The Kemp elimination (reaction of benzisoxazole with base to give 2-cyanophenolate) is catalyzed in the cavity of a cubic M8L12 coordination cage because of a combination of (i) benzisoxazole binding in the cage cavity driven by the hydrophobic effect, and (ii) accumulation of hydroxide ions around the 16+ cage surface driven by ion-pairing. Here we show how reaction of the cavity-bound guest is modified by the presence of other anions which can also accumulate around the cage surface and displace hydroxide, inhibiting catalysis of the cage-based reaction. Addn. of chloride or fluoride inhibits the reaction with hydroxide to the extent that a new autocatalytic pathway becomes apparent, resulting in a sigmoidal reaction profile. In this pathway the product 2-cyanophenolate itself accumulates around the cationic cage surface, acting as the base for the next reaction cycle. The affinity of different anions for the cage surface is therefore 2-cyanophenolate (generating autocatalysis) > chloride > fluoride (which both inhibit the reaction with hydroxide but cannot deprotonate the benzisoxazole guest) > hydroxide (default reaction pathway). The presence of this autocatalytic pathway demonstrates that a reaction of a cavity-bound guest can be induced with different anions around the cage surface in a controllable way; this was confirmed by adding different phenolates to the reaction, which accelerate the Kemp elimination to different extents depending on their basicity. This represents a significant step toward the goal of using the cage as a catalyst for bimol. reactions between a cavity-bound guest and anions accumulated around the surface.
- 23Tidmarsh, I. S.; Faust, T. B.; Adams, H.; Harding, L. P.; Russo, L.; Clegg, W.; Ward, M. D. Octanuclear Cubic Coordination Cages. J. Am. Chem. Soc. 2008, 130, 15167– 15175, DOI: 10.1021/ja805605y[ACS Full Text], [CAS], Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1CgtrzP&md5=22025ec0c52f6468fdf66fe8d04726b8Octanuclear Cubic Coordination CagesTidmarsh, Ian S.; Faust, Thomas B.; Adams, Harry; Harding, Lindsay P.; Russo, Luca; Clegg, William; Ward, Michael D.Journal of the American Chemical Society (2008), 130 (45), 15167-15175CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two new bis-bidentate bridging ligands were prepd., Lnaph and Lanth, 1,5-bis(3-(pyridin-2-yl)-pyrazol-1-ylmethyl)naphthalene and 9,10-bis(3-(pyridin-2-yl)-pyrazol-1-ylmethyl)anthracene, resp., which contain two chelating pyrazolyl-pyridine units connected to an arom. spacer (naphthalene-1,5-diyl and anthracene-9,10-diyl, resp.) via methylene connectors. Each of these reacts with transition metal dications having a preference for octahedral coordination geometry to afford {M8L12}16+ cages (for Lanth, M = Cu, Zn; for Lnaph, M = Co, Ni, Cd) which have an approx. cubic arrangement of metal ions with a bridging ligand spanning each of the twelve edges, and a large central cavity contg. a mixt. of anions and/or solvent mols. The cages based on Lanth have two cyclic helical {M4L4} faces, of opposite chirality, connected by four addnl. Lanth ligands as pillars; all metal centers have a meridional tris-chelate configuration. In contrast the cages based on Lnaph have (noncrystallog.) S6 symmetry, with a diagonally opposite pair of corners having a facial tris-chelate configuration with the other six being meridional. An addnl. significant difference between the two types of structure is that the cubes contg. Lanth do not show significant interligand arom. stacking interactions. However, in the cages based on Lnaph, there are six five-membered stacks of arom. ligand fragments around the periphery, each based on an alternating array of electron-rich (naphthyl) and electron-deficient (pyrazolyl-pyridine, coordinated to M2+) arom. units. A consequence of this is that the cages {M8(Lnaph)12}16+ retain their structural integrity in polar solvents, in contrast to the cages {M8(Lanth)12}16+ which dissoc. in polar solvents. Consequently, the cages {M8(Lnaph)12}16+ give NMR spectra in agreement with the symmetry obsd. in the solid state, and their fluorescence spectra (for M = Cd) display (in addn. to the normal naphthalene-based π-π* fluorescence) a lower-energy exciplex-like emission feature assocd. with a naphthyl → pyrazolyl-pyridine charge-transfer excited state arising from the π-stacking between ligands around the cage periphery.
- 24Ayme, J.-F.; Beves, J. E.; Leigh, D. A.; McBurney, R. T.; Rissanen, K.; Schultz, D. A Synthetic Molecular Pentafoil Knot. Nat. Chem. 2012, 4, 15– 20, DOI: 10.1038/nchem.1193[Crossref], [CAS], Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVagurzM&md5=34ca462ac92cab02fdcd542e617f5f04A synthetic molecular pentafoil knotAyme, Jean-Francois; Beves, Jonathon E.; Leigh, David A.; McBurney, Roy T.; Rissanen, Kari; Schultz, DavidNature Chemistry (2012), 4 (1), 15-20CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)Knots are being discovered with increasing frequency in both biol. and synthetic macromols. and have been fundamental topol. targets for chem. synthesis for the past two decades. Here, we report on the synthesis of the most complex non-DNA mol. knot prepd. to date: the self-assembly of five bis-aldehyde and five bis-amine building blocks about five metal cations and one chloride anion to form a 160-atom-loop mol. pentafoil knot (five crossing points). The structure and topol. of the knot is established by NMR spectroscopy, mass spectrometry and X-ray crystallog., revealing a sym. closed-loop double helicate with the chloride anion held at the center of the pentafoil knot by ten CH···Cl- hydrogen bonds. The one-pot self-assembly reaction features an exceptional no. of different design elements-some well precedented and others less well known within the context of directing the formation of (supra)mol. species. We anticipate that the strategies and tactics used here can be applied to the rational synthesis of other higher-order interlocked mol. architectures.
- 25Danon, J. J.; Krüger, A.; Leigh, D. A.; Lemonnier, J.-F.; Stephens, A. J.; Vitorica-Yrezabal, I. J.; Woltering, S. L. Braiding a Molecular Knot with Eight Crossings. Science 2017, 355, 159– 162, DOI: 10.1126/science.aal1619[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXms12jtQ%253D%253D&md5=eb89310ee73f9bfbcc9278eecf1131edBraiding a molecular knot with eight crossingsDanon, Jonathan J.; Krueger, Anneke; Leigh, David A.; Lemonnier, Jean-Francois; Stephens, Alexander J.; Vitorica-Yrezabal, Inigo J.; Woltering, Steffen L.Science (Washington, DC, United States) (2017), 355 (6321), 159-162CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Knots may ultimately prove just as versatile and useful at the nanoscale as at the macroscale. However, the lack of synthetic routes to all but the simplest mol. knots currently prevents systematic investigation of the influence of knotting at the mol. level. We found that it is possible to assemble four building blocks into three braided ligand strands. Octahedral iron(II) ions control the relative positions of the three strands at each crossing point in a circular triple helicate, while structural constraints on the ligands det. the braiding connections. This approach enables two-step assembly of a mol. 819 knot (I) featuring eight nonalternating crossings in a 192-atom closed loop ∼20 nm in length. The resolved metal-free 819 knot enantiomers have pronounced features in their CD spectra resulting solely from topol. chirality.
- 26Buchard, A.; Kember, M. R.; Sandeman, K. G.; Williams, C. K. A Bimetallic Iron(III) Catalyst for CO2/Epoxide Coupling. Chem. Commun. 2011, 47, 212– 214, DOI: 10.1039/C0CC02205E[Crossref], [PubMed], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFeqtLnP&md5=6666bad91bcac2c833a7fdc342ffab3eA bimetallic iron(III) catalyst for CO2/epoxide couplingBuchard, Antoine; Kember, Michael R.; Sandeman, Karl G.; Williams, Charlotte K.Chemical Communications (Cambridge, United Kingdom) (2011), 47 (1), 212-214CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A novel di-iron(III) catalyst for the copolymn. of cyclohexene oxide and CO2 to yield poly(cyclohexene carbonate), under mild conditions, is reported. The catalyst selectivity was completely changed on addn. of an ammonium co-catalyst to yield only the cis-isomer of the cyclic carbonate, also under mild conditions. Addnl., the catalyst was active for propylene carbonate and styrene carbonate prodn. at 1 atm pressure.
- 27Desai, S. P.; Ye, J.; Zheng, J.; Ferrandon, M. S.; Webber, T. E.; Platero-Prats, A. E.; Duan, J.; Garcia-Holley, P.; Camaioni, D. M.; Chapman, K. W.; Delferro, M.; Farha, O. K.; Fulton, J. L.; Gagliardi, L.; Lercher, J. A.; Penn, R. L.; Stein, A.; Lu, C. C. Well-Defined Rhodium–Gallium Catalytic Sites in a Metal–Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-Alkenes. J. Am. Chem. Soc. 2018, 140, 15309– 15318, DOI: 10.1021/jacs.8b08550[ACS Full Text], [CAS], Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvF2mtLnN&md5=3e0d65df531f54b47d4a3ffbe1af14d9Well-Defined Rhodium-Gallium Catalytic Sites in a Metal-Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-AlkenesDesai, Sai Puneet; Ye, Jingyun; Zheng, Jian; Ferrandon, Magali S.; Webber, Thomas E.; Platero-Prats, Ana E.; Duan, Jiaxin; Garcia-Holley, Paula; Camaioni, Donald M.; Chapman, Karena W.; Delferro, Massimiliano; Farha, Omar K.; Fulton, John L.; Gagliardi, Laura; Lercher, Johannes A.; Penn, R. Lee; Stein, Andreas; Lu, Connie C.Journal of the American Chemical Society (2018), 140 (45), 15309-15318CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-org. framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.
- 28Artem’ev, A. V.; Bagryanskaya, I. Y.; Doronina, E. P.; Tolstoy, P. M.; Gushchin, A. L.; Rakhmanova, M. I.; Ivanov, A. Y.; Suturina, A. O. A New Family of Clusters Containing a Silver-Centered Tetracapped [[email protected]4(μ3-P)4] Tetrahedron, Inscribed within a N12 Icosahedron. Dalton. Trans. 2017, 46, 12425– 12429, DOI: 10.1039/C7DT02597A[Crossref], [PubMed], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVersL3L&md5=82a696ba162e230691fbd57682f44e83A new family of clusters containing a silver-centered tetracapped [[email protected](μ3-P)4] tetrahedron, inscribed within a N12 icosahedronArtem'ev, Alexander V.; Bagryanskaya, Irina Yu.; Doronina, Evgeniya P.; Tolstoy, Peter M.; Gushchin, Artem L.; Rakhmanova, Mariana I.; Ivanov, Alexander Yu.; Suturina, Anastasiya O.Dalton Transactions (2017), 46 (37), 12425-12429CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)An unprecedented silver-centered P-tetracapped [[email protected](μ3-P)4] tetrahedron inscribed within a N12 icosahedral cage was discovered in the novel family of luminescent clusters. The latter are easily self-assembled by reacting AgI salts with tris(2-pyridyl)phosphine (Py3P).
- 29Schenck, T. G.; Downes, J. M.; Milne, C. R. C.; Mackenzie, P. B.; Boucher, T. G.; Whelan, J.; Bosnich, B. Bimetallic Reactivity. Synthesis of Bimetallic Complexes Containing a Bis(Phosphino)Pyrazole Ligand. Inorg. Chem. 1985, 24, 2334– 2337, DOI: 10.1021/ic00209a003[ACS Full Text], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXksVOiu7o%253D&md5=d8541baf671448994adb2dcd8331af1fBimetallic reactivity. Synthesis of bimetallic complexes containing a bis(phosphino)pyrazole ligandSchenck, Terry G.; Downes, J. M.; Milne, C. R. C.; Mackenzie, Peter B.; Boucher, Terry G.; Whelan, John; Bosnich, B.Inorganic Chemistry (1985), 24 (15), 2334-7CODEN: INOCAJ; ISSN:0020-1669.3,5-Bis(diphenylphosphinomethyl)pyrazole (PNNHP), which was prepd., has a geometry that provides for 2 metals to reside within cooperative distance but does not allow for metal-metal bond formation. The following planar bimetallic complexes with and without anionic bridging groups (X) were isolated and characterized: [M2(PNNP)(X)L2] (M = Pd(II), X = Cl, L = Cl; M = Rh(I), X = Cl and PPh2, L = CO; M = Ir(I), X = PPh2, L = CO) and [M2(PNNP)L4]+ (M = Pd(II), 2L = π-allyl; M = Rh(I) and Ir(I), 2L = diene and L = CO) resp.
- 30Sowa, T.; Kawamura, T.; Shida, T.; Yonezawa, T. Electronic Structure of the Rhodium-Rhodium Bond in Dirhodium Tetracarboxylates by a Study of Electronic Spectra of Neutral Molecules and Their Cation Radicals. Inorg. Chem. 1983, 22, 56– 61, DOI: 10.1021/ic00143a014[ACS Full Text], [CAS], Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXisV2nsg%253D%253D&md5=c28ea93d688070d407a03dd7eb1ffde0Electronic structure of the rhodium-rhodium bond in dirhodium tetracarboxylates by a study of electronic spectra of neutral molecules and their cation radicalsSowa, Takayoshi; Kawamura, Takashi; Shida, Tadamasa; Yonezawa, TeijiroInorganic Chemistry (1983), 22 (1), 56-61CODEN: INOCAJ; ISSN:0020-1669.Electronic absorption spectra of Rh2(O2CR)4L2 [R = Et, CF3; L = H2O, HC(CH2CH2)3N, PPh3, P(c-C6H11)3, P(OPh)3, P(OMe)3] and some of their cation radicals were examd. The intense absorption band in the near-UV region (~ν = (25-46) × 103 cm-1 and log ε = 4.0-4.7 for neutral complexes and ~ν = (17-23) × 103 cm-1 and log ε = 4.0-4.3 for cationic complexes) is assigned to the intermetallic σ → σ* transition. Ligand dependences of the transition energy and the intensity of this absorption band were interpreted with a bonding model constructed from a hypothesis that metal-ligand interactions are larger than intermetallic interactions. This valence model can also account qual. for the ligand dependences of the intermetallic bond distance and the stretching frequency of the intermetallic bond in dirhodium tetracarboxylates and the odd-electron distribution in their cation radicals. The odd electron of Rh2(O2CMe)4(H2O)2+· is probably not accommodated in the σRhRh MO. The CO stretching frequency of Rh2(O2CCF3)4(CO)2 is 7 cm-1 higher than that of the free CO, showing that there is practically no π-type interactions between the metal and the carbonyl in this complex.
- 31Bera, J. K.; Sadhukhan, N.; Majumdar, M. 1,8-Naphthyridine Revisited: Applications in Dimetal Chemistry. Eur. J. Inorg. Chem. 2009, 27, 4023– 4038, DOI: 10.1002/ejic.200900312
- 32Giordana, A.; Priola, E.; Bonometti, E.; Benzi, P.; Operti, L.; Diana, E. Structural and Spectroscopic Study of the Asymmetric 2-(2′-Pyridyl)-1,8-Naphthyridine Ligand with Closed-Shell Metals. Polyhedron 2017, 138, 239– 248, DOI: 10.1016/j.poly.2017.09.032[Crossref], [CAS], Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFylu7rL&md5=eee1cdecdb3cdcaecf7edbcf20e54806Structural and spectroscopic study of the asymmetric 2-(2'-pyridyl)-1,8-naphthyridine ligand with closed-shell metalsGiordana, Alessia; Priola, Emanuele; Bonometti, Elisabetta; Benzi, Paola; Operti, Lorenza; Diana, ElianoPolyhedron (2017), 138 (), 239-248CODEN: PLYHDE; ISSN:0277-5387. (Elsevier Ltd.)Herein, the authors report the synthesis and characterization of a series of complexes of the asym. ligand 2-(2'-pyridyl)-1,8-naphthyridine (pyNP, 1) with different closed-shell metals. For the first time ligand pyNP has been structurally and vibrationally characterized. The geometry of the pyNP ligand, with 3 N donor sites, can favor metallophilic interaction in complexes, so the authors performed a study on its coordination chem. with different metals (Ag(I), Hg(II) and Pb(II)). Twelve new complexes, namely [Ag2(pyNP)2(NO3)2] (2), [Hg(pyNP)X2](X = Cl(3), Br(4), I(5), CN(6), SCN(7, 8)), [Pb(pyNP)2(NO3)2] (9), [Pb(pyNP)(NO3)2]2 (10), [Cu(pyNP)Cl2(H2O)] (11), [Cu(pyNP)2(H2O)][Hg2(CN)4Cl2]-H2O (12) and [Cu(pyNP)(H2O)2(μ-CN)Hg2(CN)3Cl2]-H2O (13), have been synthesized and characterized by single crystal x-ray diffraction, Raman, FTIR and electronic spectroscopies. Structure of complex 2 shows a supported argentophilic interaction, and is the first structure in which pyNP bonds two previously unbounded metal centers.
- 33Dong, Y.-B.; Geng, Y.; Ma, J.-P.; Huang, R.-Q. Organometallic Silver(I) Supramolecular Complexes Generated from Multidentate Furan-Containing Symmetric and Unsymmetric Fulvene Ligands and Silver(I) Salts. Inorg. Chem. 2005, 44, 1693– 1703, DOI: 10.1021/ic048518h[ACS Full Text], [CAS], Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXovFSrtA%253D%253D&md5=7dc712f0155ff64706e2bd2c3264b35cOrganometallic Silver(I) Supramolecular Complexes Generated from Multidentate Furan-Containing Symmetric and Unsymmetric Fulvene Ligands and Silver(I) SaltsDong, Yu-Bin; Geng, Yan; Ma, Jian-Ping; Huang, Ru-QiInorganic Chemistry (2005), 44 (6), 1693-1703CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)One new conjugated sym. fulvene ligand L1 (I, R = 2-furyl) and two new unsym. fulvene ligands L2 and L3 (I, R = 4- and 3-cyanophenyl, resp.) were synthesized. Five new supramol. complexes, Ag2(L1)3(SO3CF3)3 (1, monoclinic, space group P21/c; a 12.702(3), b 26.118(7), c 13.998(4) Å, β 96.063(4)°, Z = 4), [Ag(L1)]ClO4 (2, monoclinic, space group C2/c; a 17.363(2), b 13.2794(18), c 13.4884(18) Å, β 100.292(2)°, Z = 8), [Ag(L1)(C6H6)SbF6]·0.5C6H6·H2O (3, monoclinic, P21/c; a 6.8839(11), b 20.242(3), c 18.934(3) Å, β 91.994(3)°, Z = 4), Ag(L2)(SO3CF3) (4, triclinic, P‾1; a 8.629(3), b 10.915(3), c 11.178(3) Å, α 100.978(4), β 91.994(3), γ 105.652(4)°, Z = 2), and Ag(L3)(H2O)(SO3CF3) (5, triclinic, P‾1; a 8.914(5), b 10.809(6), c 11.283(6) Å, α 69.255(8), β 87.163(9), γ 84.993(8)°, Z = 2) were obtained through self-assembly based on these three new fulvene ligands in a benzene/toluene mixed-solvent system. Compds. 1-5 were fully characterized by IR spectroscopy, elemental anal., and single-crystal x-ray diffraction. The coordination chem. of new fulvene ligands is versatile. They can adopt either cis- or trans-conformation to bind soft acid Ag(I) ion through not only the terminal -CN and furan functional groups but also the fulvene carbon atoms into organometallic coordination polymers or discrete complexes. The luminescent properties of L1-L3 and their Ag(I) complexes were studied preliminarily in EtOH and solid state.
- 34Yue, N. L. S.; Jennings, M. C.; Puddephatt, R. J. Disilver(I) Macrocycles: Variation of Cavity Size with Anion Binding. Inorg. Chem. 2005, 44, 1125– 1131, DOI: 10.1021/ic048549c[ACS Full Text], [CAS], Google Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmsVWisA%253D%253D&md5=dbb464b2bb9c55f221e65962ca4c2118Disilver(I) Macrocycles: Variation of Cavity Size with Anion BindingYue, Nancy L. S.; Jennings, Michael C.; Puddephatt, Richard J.Inorganic Chemistry (2005), 44 (4), 1125-1131CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Reaction of the N-methylated bis(amidopyridine) ligand, LL = C6H4(1,3-CONMe-4-C5H4N)2, with AgNO3, AgO2CCF3, AgO3SCF3, AgBF4, and AgPF6 gave the corresponding cationic disilver(I) macrocycles [Ag2(μ-LL)2]X2, 2a-e, resp. The transannular Ag···silver distance in the macrocycles varies greatly from 2.99 to 7.03 Å, and these differences arise through a combination of different modes of anion binding and from the presence or absence of Ag···silver secondary bonding. In all complexes, the ligand adopts a conformation in which the Me group and O atom of the MeNCO units are mutually cis, but the overall macrocycle can exist in either boat (X = PF6 only) or chair conformation. Short transannular Ag···silver distances are found in complexes 2b,c, in which the anions CF3CO2- and CF3SO3- bind above and below the macrocycle, but longer Ag···silver distances are found for 2a,d,e, in which the anions are present, at least in part, inside the disilver macrocycle. Easy anion exchange occurs in soln., and studies using ESI-MS indicate that the anion binding to form [Ag2X(μ-LL)2]+ follows the sequence X = CF3CO2- > NO3- > CF3SO3-.
- 35Beauchamp, D. A.; Loeb, S. J. Molecular Squares, Rectangles and Infinite Helical Chains Utilising the Simple ‘Corner’ Ligand 4-(2-Pyridyl)-Pyrimidine. Chem. Commun. 2002, 2484– 2485, DOI: 10.1039/B206989J[Crossref], [CAS], Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotVylsr0%253D&md5=0911c2c4fba33b3bf73c31a774a023e0Molecular squares, rectangles and infinite helical chains utilising the simple corner' ligand 4-(2-pyridyl)pyrimidineBeauchamp, Derek A.; Loeb, Stephen J.Chemical Communications (Cambridge, United Kingdom) (2002), (21), 2484-2485CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The ligand 4-(2-pyridyl)pyrimidine (L) forms multinuclear Ag(I) complexes, {[AgL]X}4 (X = BF4, triflate) and {[AgL]NO3}n by a combination of chelating and bridging coordination modes. Mol. shape (square or rectangle) and degree of aggregation depend on the anion used. In {[AgL]BF4}4 (triclinic, space group P‾1, Z = 1, R1 = 0.0712, wR1 = 0.0724) each Ag is pseudo-trigonal. In {[AgL]O3SCF3}4 (triclinic, space group P‾1, Z = 1, R1 = 0.0279, wR1 = 0.0299) the complex cation is rectangular with 2 Ag atoms 2-coordinate and 2 Ag atoms tetrahedral. In {[AgL]NO3}n (monoclinic, space group P21/n, Z = 4, R1 = 0.0279, wR1 = 0.0299) the Ag atoms are coordinated by the bidentate L and NO3- in an infinite chain.
- 36Wiley, C. A.; Holloway, L. R.; Miller, T. F.; Lyon, Y.; Julian, R. R.; Hooley, R. J. Electronic Effects on Narcissistic Self-Sorting in Multicomponent Self-Assembly of Fe-Iminopyridine Meso-Helicates. Inorg. Chem. 2016, 55, 9805– 9815, DOI: 10.1021/acs.inorgchem.6b01644[ACS Full Text], [CAS], Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2iu7nL&md5=57b3a5d49525f0436fea780533d6abd6Electronic Effects on Narcissistic Self-Sorting in Multicomponent Self-Assembly of Fe-Iminopyridine meso-HelicatesWiley, Calvin A.; Holloway, Lauren R.; Miller, Tabitha F.; Lyon, Yana; Julian, Ryan. R.; Hooley, Richard J.Inorganic Chemistry (2016), 55 (19), 9805-9815CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Small changes in the electron donating ability of coordinating groups have substantial effects on the multicomponent self-assembly of Fe(II)-iminopyridine-based meso-helicate complexes. Both the nature of the internal diamine core and the terminal formylpyridine reactants control the rate of the assembly process, the thermodn. favorability of the meso-helicate products, and the selective incorporation of different aldehyde termini into the assembly. Steric congestion at the coordinating ligands can prevent assembly altogether, and favorable incorporation of electron-rich aldehyde termini is obsd., even though the rate of reaction is accelerated using electron-poor aldehyde reactants. NMR and electrospray ionization mass spectrometry analyses were employed to det. the synergistic nature of narcissistic self-sorting in this system, which depends on both the rigidity of the central core and the electronic donor ability of the aldehyde terminus. These expts. illustrate that significant control of self-sorting and self-assembly is possible upon extremely small variations in ligand structure, rigidity, and donor ability.
- 37Ronson, T. K.; Zarra, S.; Black, S. P.; Nitschke, J. R. Metal–organic Container Molecules through Subcomponent Self-Assembly. Chem. Commun. 2013, 49, 2476– 2490, DOI: 10.1039/c2cc36363a[Crossref], [PubMed], [CAS], Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlyjt7o%253D&md5=5ec9fdb77f4f246615a5e3c77b7e7b4bMetal-organic container molecules through subcomponent self-assemblyRonson, Tanya K.; Zarra, Salvatore; Black, Samuel P.; Nitschke, Jonathan R.Chemical Communications (Cambridge, United Kingdom) (2013), 49 (25), 2476-2490CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A review. A variety of different three-dimensional metal-org. container mols. have recently been prepd. using subcomponent self-assembly, which relies upon metal template effects to generate complex structures from simple mol. precursors and metal salts. Many of these structures have well defined internal pockets, allowing guest species to be bound and the chem. reactivity of these guests to be modified. Such host mols. have potential applications ranging from the protection of sensitive chem. species to the sepn. and purifn. of substrates as diverse as gases, gold compds., and fullerenes.
- 38Mosquera, J.; Ronson, T. K.; Nitschke, J. Subcomponent Flexibility Enables Conversion between D4-Symmetric CdII8L8 and T-Symmetric CdII4L4 Assemblies. J. Am. Chem. Soc. 2016, 138, 1812– 1815, DOI: 10.1021/jacs.5b12955[ACS Full Text], [CAS], Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVGktbs%253D&md5=9f3adadd61dab3a2c13122aadca955f2Subcomponent Flexibility Enables Conversion between D4-Symmetric CdII8L8 and T-Symmetric CdII4L4 AssembliesMosquera, Jesus; Ronson, Tanya K.; Nitschke, Jonathan R.Journal of the American Chemical Society (2016), 138 (6), 1812-1815CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A flexible tris-formylpyridine subcomponent A (I) was obsd. to produce three distinct products following CdII-templated self-assembly with different anilines. Two of the products were CdII4L4 tetrahedra (C192H172Cd4F48N32O46S16), one with ligands puckered inward, and the other outward. The third product was a CdII8L8 structure (C399H382.5Cd8F48N63.5O72S16) having all mer stereochem., contrasting with the fac stereochem. of the tetrahedra. These three complexes coexist in soln. The equil. between them could be influenced through guest binding and specific interactions between aniline subcomponents, allowing a selected one of the three to predominate under defined conditions.
- 39Fatila, E. M.; Twum, E. B.; Karty, J. A.; Flood, A. H. Ion Pairing and Co-Facial Stacking Drive High-Fidelity Bisulfate Assembly with Cyanostar Macrocyclic Hosts. Chem. - Eur. J. 2017, 23, 10652– 10662, DOI: 10.1002/chem.201701763[Crossref], [PubMed], [CAS], Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFOltrnK&md5=28a6c157e2472efedea70b7258fda2e1Ion Pairing and Co-facial Stacking Drive High-Fidelity Bisulfate Assembly with Cyanostar Macrocyclic HostsFatila, Elisabeth M.; Twum, Eric B.; Karty, Jonathan A.; Flood, Amar H.Chemistry - A European Journal (2017), 23 (44), 10652-10662CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Hydroxyanions pair up inside CH H-bonding cyanostar macrocycles, I, against Coulombic repulsions and solvation forces acting to sep. them. The driving forces responsible for assembly of bisulfate (HSO4-) dimers are unclear. We investigated them using solvent quality to tune the contributing forces and we take advantage of characteristic NMR signatures to follow the species distributions. We show that apolar solvents enhance ion pairing to stabilize formation of a 2:2:2 complex composed of π-stacked cyanostars encapsulating the [HSO4···HSO4]2- dimer and endcapped by tetrabutylammonium cations. Without cations engaged, a third macrocycle can be recruited with the aid of solvophobic forces in more polar solvents. The third macrocycle generates a more potent electropos. pocket in which to stabilize the anti-electrostatic anion dimer as a 3:2 assembly. We also see unprecedented evidence for a water mol. bound to the complex in the acetonitrile soln. In methanol, OH H-bonding leads to formation of 2:1 complexes by bisulfate solvation inside the macrocycles inhibiting anion dimers. Knowledge of the driving forces for stabilization (strong OH···O H-bonding, CH H-bonding, ion pairs, π-stacking) competing with destabilization (Coulomb repulsion, solvation) allows high-fidelity selection of the assemblies. Thermodn. stabilization of hydroxyanion dimers also demonstrates the ability to use macrocycles to control ion speciation and stoichiometry of the overall assemblies.
- 40Dobscha, J. R.; Debnath, S.; Fadler, R. E.; Fatila, E. M.; Pink, M.; Raghavachari, K.; Flood, A. H. Host-Host Interactions Control Self-Assembly and Switching of Triple and Double Decker Stacks of Tricarbazole Macrocycles Co-Assembled with Anti-Electrostatic Bisulfate Dimers. Chem. - Eur. J. 2018, 24, 9841– 9852, DOI: 10.1002/chem.201800827[Crossref], [PubMed], [CAS], Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtFGks7rJ&md5=9601acada1186918b4498c6391d9a09cHost-Host Interactions Control Self-assembly and Switching of Triple and Double Decker Stacks of Tricarbazole Macrocycles Co-assembled with anti-Electrostatic Bisulfate DimersDobscha, James R.; Debnath, Sibali; Fadler, Rachel E.; Fatila, Elisabeth M.; Pink, Maren; Raghavachari, Krishnan; Flood, Amar H.Chemistry - A European Journal (2018), 24 (39), 9841-9852CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Tricarbazole triazolophanes I [R = Me(CH2)n; n = 5, 8] were prepd.; I (n = 8) formed self-assembled 2:2 and 3:2 complexes with tetrabutylammonium bisulfate in 20% MeCN/CHCl3 and CHCl3, resp. In CHCl3, I formed high fidelity, triple-decker stacks with bisulfate dimers because of the greater strength of host-host interactions than of the ion-pairing interaction seen in more weakly-interacting oligomers. X-ray crystallog. of the 2:2:2 complex I·Bu4N+·HSO4- supported the idea that significant host-host interactions with I arise from dipole-stabilized π-stacking. Calcd. structures and free energies of solvation for model compds. further highlight the importance of host-host interactions in stacked complexes of I.
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Substantial disorder of the oxygen atoms of the encapsulated HSO4– anions precluded accurate resolution of the hydrogen atom of these anions. However, the observed distance between the disordered HSO4– anions is consistent with the presence of a hydrogen-bonded dimer.
There is no corresponding record for this reference. - 42Bravin, C.; Guidetti, A.; Licini, G.; Zonta, C. Supramolecular Cages as Differential Sensors for Dicarboxylate Anions: Guest Length Sensing Using Principal Component Analysis of ESI-MS and 1H-NMR Raw Data. Chem. Sci. 2019, 10, 3523– 3528, DOI: 10.1039/C8SC05527K[Crossref], [PubMed], [CAS], Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXisFWlsb0%253D&md5=2489cdd6fa388eb9294bf85f481638eaSupramolecular cages as differential sensors for dicarboxylate anions: guest length sensing using principal component analysis of ESI-MS and 1H-NMR raw dataBravin, Carlo; Guidetti, Andrea; Licini, Giulia; Zonta, CristianoChemical Science (2019), 10 (12), 3523-3528CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Dynamic covalent libraries (DCLs) have been widely used in the development of differential sensors. Inspired by recent studies which use supramol. recognition systems for sensing, we report the use of a tris(-pyridylmethyl)amine (TPMA)-based supramol. cage as a differential sensor for dicarboxylate anions. In particular, a library of mol. cages constituted by linkers differing in size and flexibility was allowed to equilibrate toward a series of guests differing in mol. size. The differential system was able to discriminate a series of dicarboxylates depending on their chain length. This differentiation was evaluated through the application of the Principal Component Anal. (PCA) method using interpolated and raw data obtained from ESI-MS. Interestingly, while the 1H NMR spectra of the differential system did not allow for the discrimination of the analytes by the naked eye, PCA of the raw data from the spectra revealed information on the chain length of the guest and also on the odd-even character of the carbon chain.
- 43Clever, G. H.; Kawamura, W.; Shionoya, M. Encapsulation versus Aggregation of Metal–Organic Cages Controlled by Guest Size Variation. Inorg. Chem. 2011, 50, 4689– 4691, DOI: 10.1021/ic200517r[ACS Full Text], [CAS], Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXltFGmsbY%253D&md5=fe5c398c6930d0df1174cce751b71d0dEncapsulation versus Aggregation of Metal-Organic Cages Controlled by Guest Size VariationClever, Guido H.; Kawamura, Wataru; Shionoya, MitsuhikoInorganic Chemistry (2011), 50 (11), 4689-4691CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The strength and mode of binding (inside vs. outside) of arenedisulfonate bisanionic guest mols. to a cationic, self-assembled dinuclear palladium metal-org. cage depend on their size and the stoichiometry of the addn. Herein the compn. of the solid/liq. phase of a heterogeneous system can be kinetically controlled by the order of the addn. of two different guest compds.
- 44Minisci, F.; Citterio, A.; Giordano, C. Electron-Transfer Processes: Peroxydisulfate, a Useful and Versatile Reagent in Organic Chemistry. Acc. Chem. Res. 1983, 16, 27– 32, DOI: 10.1021/ar00085a005[ACS Full Text], [CAS], Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXlt1OhtA%253D%253D&md5=fa910a18ba21cc9a983724c3c61940dfElectron-transfer processes: peroxydisulfate, a useful and versatile reagent in organic chemistryMinisci, Francesco; Citterio, Attilio; Giordano, ClaudioAccounts of Chemical Research (1983), 16 (1), 27-32CODEN: ACHRE4; ISSN:0001-4842.A review with >40 refs.
Supporting Information
Supporting Information
ARTICLE SECTIONSThe Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/jacs.9b05432.
Detailed descriptions of synthetic procedures; characterization of new compounds; spectroscopic data (PDF)
X-ray data for (OTf–/PF6–)2⊂1 (CCDC 1913634) (CIF), (ClO4–)2⊂1 (CCDC 1913631) (CIF), (HSO4–)2⊂1 (CCDC 1913633) (CIF), (EDS2–)⊂1 (CCDC 1913632) (CIF), and (S2O82–)⊂1 (CCDC 1913635) (CIF)
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